diff --git a/internal/s3/client.go b/internal/s3/client.go
index 658f737..820e74d 100644
--- a/internal/s3/client.go
+++ b/internal/s3/client.go
@@ -79,6 +79,10 @@ func (c *Client) Multipart(bucket, key string, objPartSize int, payload goja.Arr
 		stats.Report(c.vu, objPutFails, 1)
 		return PutResponse{Success: false, Error: fmt.Sprintf("part size '%d' must be greater than '%d'(5 MB)", objPartSize, multipartUploadMinPartSize)}
 	}
+	if concurrency == 0 {
+		stats.Report(c.vu, objPutFails, 1)
+		return PutResponse{Success: false, Error: fmt.Sprintf("number of parts to upload in parallel must be greater than 0")}
+	}
 	start := time.Now()
 	uploader := manager.NewUploader(c.cli, func(u *manager.Uploader) {
 		u.PartSize = int64(objPartSize)