diff --git a/pkg/smartcontract/param_context.go b/pkg/smartcontract/param_context.go
index fe8a2561b..b1b8e3330 100644
--- a/pkg/smartcontract/param_context.go
+++ b/pkg/smartcontract/param_context.go
@@ -46,21 +46,94 @@ type rawParameter struct {
 	Value json.RawMessage `json:"value"`
 }
 
+type keyValuePair struct {
+	Key   rawParameter `json:"key"`
+	Value rawParameter `json:"value"`
+}
+
+type rawKeyValuePair struct {
+	Key   json.RawMessage `json:"key"`
+	Value json.RawMessage `json:"value"`
+}
+
+// MarshalJSON implements Marshaler interface.
+func (p *Parameter) MarshalJSON() ([]byte, error) {
+	var (
+		resultRawValue json.RawMessage
+		resultErr            error
+	)
+	switch p.Type {
+	case BoolType, IntegerType, StringType, Hash256Type, Hash160Type:
+		resultRawValue, resultErr = json.Marshal(p.Value)
+	case PublicKeyType, ByteArrayType, SignatureType:
+		resultRawValue, resultErr = json.Marshal(hex.EncodeToString(p.Value.([]byte)))
+	case ArrayType:
+		var value = make([]rawParameter, 0)
+		for _, parameter := range p.Value.([]Parameter) {
+			rawValue, err := json.Marshal(parameter.Value)
+			if err != nil {
+				return nil, err
+			}
+			value = append(value, rawParameter{
+				Type:  parameter.Type,
+				Value: rawValue,
+			})
+		}
+		resultRawValue, resultErr = json.Marshal(value)
+	case MapType:
+		var value []keyValuePair
+		for key, val := range p.Value.(map[Parameter]Parameter) {
+			rawKey, err := json.Marshal(key.Value)
+			if err != nil {
+				return nil, err
+			}
+			rawValue, err := json.Marshal(val.Value)
+			if err != nil {
+				return nil, err
+			}
+			value = append(value, keyValuePair{
+				Key: rawParameter{
+					Type:  key.Type,
+					Value: rawKey,
+				},
+				Value: rawParameter{
+					Type:  val.Type,
+					Value: rawValue,
+				},
+			})
+		}
+		resultRawValue, resultErr = json.Marshal(value)
+	default:
+		resultErr = errors.Errorf("Marshaller for type %s not implemented", p.Type)
+	}
+	if resultErr != nil {
+		return nil, resultErr
+	}
+	return json.Marshal(rawParameter{
+		Type:  p.Type,
+		Value: resultRawValue,
+	})
+}
+
 // UnmarshalJSON implements Unmarshaler interface.
 func (p *Parameter) UnmarshalJSON(data []byte) (err error) {
 	var (
-		r rawParameter
-		i int64
-		s string
-		b []byte
+		r       rawParameter
+		i       int64
+		s       string
+		b       []byte
+		boolean bool
 	)
-
 	if err = json.Unmarshal(data, &r); err != nil {
 		return
 	}
-
 	switch p.Type = r.Type; r.Type {
-	case ByteArrayType:
+	case BoolType:
+		if err = json.Unmarshal(r.Value, &boolean); err != nil {
+			return
+		}
+		p.Value = boolean
+	case ByteArrayType, PublicKeyType:
 		if err = json.Unmarshal(r.Value, &s); err != nil {
 			return
 		}
@@ -93,6 +166,23 @@ func (p *Parameter) UnmarshalJSON(data []byte) (err error) {
 			return
 		}
 		p.Value = rs
+	case MapType:
+		var rawMap []rawKeyValuePair
+		if err = json.Unmarshal(r.Value, &rawMap); err != nil {
+			return
+		}
+		rs := make(map[Parameter]Parameter)
+		for _, p := range rawMap {
+			var key, value Parameter
+			if err = json.Unmarshal(p.Key, &key); err != nil {
+				return
+			}
+			if err = json.Unmarshal(p.Value, &value); err != nil {
+				return
+			}
+			rs[key] = value
+		}
+		p.Value = rs
 	case Hash160Type:
 		var h util.Uint160
 		if err = json.Unmarshal(r.Value, &h); err != nil {
@@ -106,7 +196,7 @@ func (p *Parameter) UnmarshalJSON(data []byte) (err error) {
 		}
 		p.Value = h
 	default:
-		return errors.New("not implemented")
+		return errors.Errorf("Unmarshaller for type %s not implemented", p.Type)
 	}
 	return
 }
diff --git a/pkg/smartcontract/param_context_test.go b/pkg/smartcontract/param_context_test.go
index 288c8558c..1a188a4be 100644
--- a/pkg/smartcontract/param_context_test.go
+++ b/pkg/smartcontract/param_context_test.go
@@ -2,6 +2,7 @@ package smartcontract
 
 import (
 	"encoding/json"
+	"math"
 	"reflect"
 	"testing"
 
@@ -9,10 +10,129 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-var testCases = []struct {
+var marshalJSONTestCases = []struct {
+	input  Parameter
+	result string
+}{
+	{
+		input:  Parameter{Type: IntegerType, Value: int64(12345)},
+		result: `{"type":"Integer","value":12345}`,
+	},
+	{
+		input:  Parameter{Type: StringType, Value: "Some string"},
+		result: `{"type":"String","value":"Some string"}`,
+	},
+	{
+		input:  Parameter{Type: BoolType, Value: true},
+		result: `{"type":"Boolean","value":true}`,
+	},
+	{
+		input:  Parameter{Type: ByteArrayType, Value: []byte{0x01, 0x02, 0x03}},
+		result: `{"type":"ByteArray","value":"010203"}`,
+	},
+	{
+		input: Parameter{
+			Type:  PublicKeyType,
+			Value: []byte{0x03, 0xb3, 0xbf, 0x15, 0x02, 0xfb, 0xdc, 0x05, 0x44, 0x9b, 0x50, 0x6a, 0xaf, 0x04, 0x57, 0x97, 0x24, 0x02, 0x4b, 0x06, 0x54, 0x2e, 0x49, 0x26, 0x2b, 0xfa, 0xa3, 0xf7, 0x0e, 0x20, 0x00, 0x40, 0xa9},
+		},
+		result: `{"type":"PublicKey","value":"03b3bf1502fbdc05449b506aaf04579724024b06542e49262bfaa3f70e200040a9"}`,
+	},
+	{
+		input: Parameter{
+			Type: ArrayType,
+			Value: []Parameter{
+				{Type: StringType, Value: "str 1"},
+				{Type: IntegerType, Value: int64(2)},
+			},
+		},
+		result: `{"type":"Array","value":[{"type":"String","value":"str 1"},{"type":"Integer","value":2}]}`,
+	},
+	{
+		input: Parameter{
+			Type: MapType,
+			Value: map[Parameter]Parameter{
+				{Type: StringType, Value: "key1"}: {Type: IntegerType, Value: 1},
+				{Type: StringType, Value: "key2"}: {Type: StringType, Value: "two"},
+			},
+		},
+		result: `{"type":"Map","value":[{"key":{"type":"String","value":"key1"},"value":{"type":"Integer","value":1}},{"key":{"type":"String","value":"key2"},"value":{"type":"String","value":"two"}}]}`,
+	},
+	{
+		input: Parameter{
+			Type: MapType,
+			Value: map[Parameter]Parameter{
+				{Type: StringType, Value: "key1"}: {Type: ArrayType, Value: []Parameter{
+					{Type: StringType, Value: "str 1"},
+					{Type: IntegerType, Value: int64(2)},
+				}},
+			},
+		},
+		result: `{"type":"Map","value":[{"key":{"type":"String","value":"key1"},"value":{"type":"Array","value":[{"type":"String","value":"str 1"},{"type":"Integer","value":2}]}}]}`,
+	},
+	{
+		input: Parameter{
+			Type: Hash160Type,
+			Value: util.Uint160{
+				0x0b, 0xcd, 0x29, 0x78, 0x63, 0x4d, 0x96, 0x1c, 0x24, 0xf5,
+				0xae, 0xa0, 0x80, 0x22, 0x97, 0xff, 0x12, 0x87, 0x24, 0xd6,
+			},
+		},
+		result: `{"type":"Hash160","value":"0x0bcd2978634d961c24f5aea0802297ff128724d6"}`,
+	},
+	{
+		input: Parameter{
+			Type: Hash256Type,
+			Value: util.Uint256{
+				0x2d, 0xf3, 0x45, 0xf2, 0x45, 0xc5, 0x98, 0x9e,
+				0x69, 0x95, 0x45, 0x06, 0xa5, 0x9e, 0x40, 0x12,
+				0xc1, 0x68, 0x54, 0x48, 0x08, 0xfc, 0xcc, 0x5b,
+				0x15, 0x18, 0xab, 0xa0, 0x8f, 0x30, 0x37, 0xf0,
+			},
+		},
+		result: `{"type":"Hash256","value":"0xf037308fa0ab18155bccfc08485468c112409ea5064595699e98c545f245f32d"}`,
+	},
+}
+
+var marshalJSONErrorCases = []Parameter{
+	{
+		Type:  UnknownType,
+		Value: nil,
+	},
+	{
+		Type:  InteropInterfaceType,
+		Value: nil,
+	},
+	{
+		Type:  IntegerType,
+		Value: math.Inf(1),
+	},
+}
+
+func TestParam_MarshalJSON(t *testing.T) {
+	for _, tc := range marshalJSONTestCases {
+		res, err := json.Marshal(&tc.input)
+		assert.NoError(t, err)
+		var actual, expected Parameter
+		assert.NoError(t, json.Unmarshal(res, &actual))
+		assert.NoError(t, json.Unmarshal([]byte(tc.result), &expected))
+
+		assert.Equal(t, expected, actual)
+	}
+
+	for _, input := range marshalJSONErrorCases {
+		_, err := json.Marshal(&input)
+		assert.Error(t, err)
+	}
+}
+
+var unmarshalJSONTestCases = []struct {
 	input  string
 	result Parameter
 }{
+	{
+		input:  `{"type":"Bool","value":true}`,
+		result: Parameter{Type: BoolType, Value: true},
+	},
 	{
 		input:  `{"type":"Integer","value":12345}`,
 		result: Parameter{Type: IntegerType, Value: int64(12345)},
@@ -63,9 +183,38 @@ var testCases = []struct {
 			},
 		},
 	},
+	{
+		input: `{"type":"Map","value":[{"key":{"type":"String","value":"key1"},"value":{"type":"Integer","value":1}},{"key":{"type":"String","value":"key2"},"value":{"type":"String","value":"two"}}]}`,
+		result: Parameter{
+			Type: MapType,
+			Value: map[Parameter]Parameter{
+				{Type: StringType, Value: "key1"}: {Type: IntegerType, Value: int64(1)},
+				{Type: StringType, Value: "key2"}: {Type: StringType, Value: "two"},
+			},
+		},
+	},
+	{
+		input: `{"type":"Map","value":[{"key":{"type":"String","value":"key1"},"value":{"type":"Array","value":[{"type":"String","value":"str 1"},{"type":"Integer","value":2}]}}]}`,
+		result: Parameter{
+			Type: MapType,
+			Value: map[Parameter]Parameter{
+				{Type: StringType, Value: "key1"}: {Type: ArrayType, Value: []Parameter{
+					{Type: StringType, Value: "str 1"},
+					{Type: IntegerType, Value: int64(2)},
+				}},
+			},
+		},
+	},
+	{
+		result: Parameter{
+			Type:  PublicKeyType,
+			Value: []byte{0x03, 0xb3, 0xbf, 0x15, 0x02, 0xfb, 0xdc, 0x05, 0x44, 0x9b, 0x50, 0x6a, 0xaf, 0x04, 0x57, 0x97, 0x24, 0x02, 0x4b, 0x06, 0x54, 0x2e, 0x49, 0x26, 0x2b, 0xfa, 0xa3, 0xf7, 0x0e, 0x20, 0x00, 0x40, 0xa9},
+		},
+		input: `{"type":"PublicKey","value":"03b3bf1502fbdc05449b506aaf04579724024b06542e49262bfaa3f70e200040a9"}`,
+	},
 }
 
-var errorCases = []string{
+var unmarshalJSONErrorCases = []string{
 	`{"type": "ByteArray","value":`,        // incorrect JSON
 	`{"type": "ByteArray","value":1}`,      // incorrect Value
 	`{"type": "ByteArray","value":"12zz"}`, // incorrect ByteArray value
@@ -78,19 +227,23 @@ var errorCases = []string{
 	`{"type": "Hash256","value": "0bcd"}`,  // incorrect Uint256 value
 	`{"type": "Stringg","value": ""}`,      // incorrect type
 	`{"type": {},"value": ""}`,             // incorrect value
+	`{"type": "Boolean","value": qwerty}`,  // incorrect Bool value
+	`{"type": "Boolean","value": ""}`,      // incorrect Bool value
+	`{"type": "Map","value": ["key": {}]}`, // incorrect Map value
+	`{"type": "Map","value": ["key": {"type":"String", "value":"qwer"}, "value": {"type":"Boolean"}]}`, // incorrect Map Value value
+	`{"type": "Map","value": ["key": {"type":"String"}, "value": {"type":"Boolean", "value":true}]}`,   // incorrect Map Key value
 
 	`{"type": "InteropInterface","value": ""}`, // ununmarshable type
-	`{"type": "Map","value": ""}`,              //unmarshable type
 }
 
 func TestParam_UnmarshalJSON(t *testing.T) {
 	var s Parameter
-	for _, tc := range testCases {
+	for _, tc := range unmarshalJSONTestCases {
 		assert.NoError(t, json.Unmarshal([]byte(tc.input), &s))
 		assert.Equal(t, s, tc.result)
 	}
 
-	for _, input := range errorCases {
+	for _, input := range unmarshalJSONErrorCases {
 		assert.Error(t, json.Unmarshal([]byte(input), &s))
 	}
 }