diff --git a/graphenej/src/main/java/cy/agorise/graphenej/operations/CreateHtlcOperation.java b/graphenej/src/main/java/cy/agorise/graphenej/operations/CreateHtlcOperation.java
index 0b41b2c..bbd8946 100644
--- a/graphenej/src/main/java/cy/agorise/graphenej/operations/CreateHtlcOperation.java
+++ b/graphenej/src/main/java/cy/agorise/graphenej/operations/CreateHtlcOperation.java
@@ -1,6 +1,10 @@
 package cy.agorise.graphenej.operations;
 
 import com.google.common.primitives.Bytes;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonArray;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
 
 import cy.agorise.graphenej.AssetAmount;
 import cy.agorise.graphenej.BaseOperation;
@@ -10,6 +14,13 @@ import cy.agorise.graphenej.UserAccount;
 import cy.agorise.graphenej.Util;
 
 public class CreateHtlcOperation extends BaseOperation {
+    static final String KEY_FROM = "from";
+    static final String KEY_TO = "to";
+    static final String KEY_AMOUNT = "amount";
+    static final String KEY_PREIMAGE_HASH = "preimage_hash";
+    static final String KEY_PREIMAGE_SIZE = "preimage_size";
+    static final String KEY_CLAIM_PERIOD_SECONDS = "claim_period_seconds";
+
     private AssetAmount fee;
     private UserAccount from;
     private UserAccount to;
@@ -110,8 +121,26 @@ public class CreateHtlcOperation extends BaseOperation {
         return Bytes.concat(feeBytes, fromBytes, toBytes, amountBytes, htlcHashBytes, preimageSizeBytes, claimPeriodBytes, extensionsBytes);
     }
 
+    @Override
+    public JsonElement toJsonObject() {
+        JsonArray array = new JsonArray();
+        array.add(this.getId());
+        JsonObject jsonObject = new JsonObject();
+        jsonObject.add(KEY_FEE, fee.toJsonObject());
+        jsonObject.addProperty(KEY_FROM, from.getObjectId());
+        jsonObject.addProperty(KEY_TO, to.getObjectId());
+        jsonObject.add(KEY_AMOUNT, amount.toJsonObject());
+        jsonObject.add(KEY_PREIMAGE_HASH, preimageHash.toJsonObject());
+        jsonObject.addProperty(KEY_PREIMAGE_SIZE, preimageSize);
+        jsonObject.addProperty(KEY_CLAIM_PERIOD_SECONDS, claimPeriodSeconds);
+        jsonObject.add(KEY_EXTENSIONS, new JsonArray());
+        array.add(jsonObject);
+        return array;
+    }
+
     @Override
     public String toJsonString() {
-        return null;
+        GsonBuilder gsonBuilder = new GsonBuilder();
+        return gsonBuilder.create().toJson(this);
     }
 }
diff --git a/graphenej/src/test/java/cy/agorise/graphenej/operations/CreateHtlcOperationTest.java b/graphenej/src/test/java/cy/agorise/graphenej/operations/CreateHtlcOperationTest.java
index 3a322b5..4c38531 100644
--- a/graphenej/src/test/java/cy/agorise/graphenej/operations/CreateHtlcOperationTest.java
+++ b/graphenej/src/test/java/cy/agorise/graphenej/operations/CreateHtlcOperationTest.java
@@ -2,6 +2,8 @@ package cy.agorise.graphenej.operations;
 
 import com.google.common.primitives.Bytes;
 import com.google.common.primitives.UnsignedLong;
+import com.google.gson.JsonArray;
+import com.google.gson.JsonObject;
 
 import org.junit.Assert;
 import org.junit.Test;
@@ -27,6 +29,7 @@ import cy.agorise.graphenej.Util;
 public class CreateHtlcOperationTest {
     private final String SERIALIZED_OP = "0000000000000000007b7c80241100000000000000a06e327ea7388c18e4740e350ed4e60f2e04fc41c8007800000000";
     private final String SERIALIZED_TX = "f68585abf4dce7c8045701310000000000000000007b7c80241100000000000000a06e327ea7388c18e4740e350ed4e60f2e04fc41c800780000000000";
+    private final String JSON_SERIALIZED_TX = "{\"expiration\":\"2016-04-06T08:29:27\",\"extensions\":[],\"operations\":[[49,{\"amount\":{\"amount\":1123456,\"asset_id\":\"1.3.0\"},\"claim_period_seconds\":120,\"extensions\":[],\"fee\":{\"amount\":0,\"asset_id\":\"1.3.0\"},\"from\":\"1.2.123\",\"preimage_hash\":[0,\"a06e327ea7388c18e4740e350ed4e60f2e04fc41\"],\"preimage_size\":200,\"to\":\"1.2.124\"}]],\"ref_block_num\":34294,\"ref_block_prefix\":3707022213,\"signatures\":[]}";
     private final String PREIMAGE_HEX = "666f6f626172";
     private final String HASH_RIPEMD160 = "a06e327ea7388c18e4740e350ed4e60f2e04fc41";
     private final String HASH_SHA1 = "8843d7f92416211de9ebb963ff4ce28125932878";
@@ -93,8 +96,19 @@ public class CreateHtlcOperationTest {
         ArrayList<BaseOperation> operations = new ArrayList<>();
         operations.add(buildCreateHtlcOperation());
         Transaction transaction = new Transaction(blockData, operations);
+        // Checking byte serialization
         byte[] txBytes = transaction.toBytes();
         byte[] expected = Bytes.concat(Util.hexToBytes(Chains.BITSHARES.CHAIN_ID), Util.hexToBytes(SERIALIZED_TX));
         Assert.assertArrayEquals(expected, txBytes);
+        // Checking JSON serialization
+        JsonObject jsonObject = transaction.toJsonObject();
+        JsonArray operationsArray = jsonObject.get("operations").getAsJsonArray().get(0).getAsJsonArray();
+        JsonArray hashArray = operationsArray.get(1).getAsJsonObject().get("preimage_hash").getAsJsonArray();
+        Assert.assertEquals("2016-04-06T08:29:27", jsonObject.get("expiration").getAsString());
+        Assert.assertEquals(49, operationsArray.get(0).getAsInt());
+        Assert.assertEquals("1.2.123", operationsArray.get(1).getAsJsonObject().get("from").getAsString());
+        Assert.assertEquals("1.2.124", operationsArray.get(1).getAsJsonObject().get("to").getAsString());
+        Assert.assertEquals(0, hashArray.get(0).getAsInt());
+        Assert.assertEquals(HASH_RIPEMD160, hashArray.get(1).getAsString());
     }
 }