diff --git a/packages/bitcore-lib/lib/script/script.js b/packages/bitcore-lib/lib/script/script.js
index 07f5ea8ffa..fe6a213e9a 100644
--- a/packages/bitcore-lib/lib/script/script.js
+++ b/packages/bitcore-lib/lib/script/script.js
@@ -157,12 +157,21 @@ Script.fromASM = function(str) {
     var opcode = Opcode(token);
     var opcodenum = opcode.toNumber();
 
-    if (opcodenum == null) {
+    if (_.isUndefined(opcodenum)) {
       var buf = Buffer.from(tokens[i], 'hex');
+      if (buf.length < 0x4c){
+        opcodenum=buf.length
+      }else if (buf.length <= 0x100) {
+        opcodenum=Opcode.OP_PUSHDATA1
+      }else if(buf.length <= 0x10000){
+        opcodenum=Opcode.OP_PUSHDATA2
+      }else if(buf.length <= 0x100000000){
+        opcodenum=Opcode.OP_PUSHDATA4
+      }
       script.chunks.push({
         buf: buf,
         len: buf.length,
-        opcodenum: buf.length
+        opcodenum: opcodenum
       });
       i = i + 1;
     } else if (opcodenum === Opcode.OP_PUSHDATA1 ||
@@ -953,6 +962,7 @@ Script.buildWitnessV1Out = function(to, scriptTree) {
     }
   }
   
+
   function buildTree(tree) {
     if (Array.isArray(tree)) {
       const [left, leftH] = buildTree(tree[0]);
diff --git a/packages/bitcore-lib/test/script/script.js b/packages/bitcore-lib/test/script/script.js
index 6bb3e622c6..b437101671 100644
--- a/packages/bitcore-lib/test/script/script.js
+++ b/packages/bitcore-lib/test/script/script.js
@@ -203,6 +203,31 @@ describe('Script', function() {
       script.chunks[3].opcodenum.should.equal(Opcode.OP_EQUALVERIFY);
       script.chunks[4].opcodenum.should.equal(Opcode.OP_CHECKSIG);
     });
+
+    it('should parse OP_PUSHDATA in ASM', function() {
+      const data0 = '01'.repeat(0x4b)
+      const data1 = '01'.repeat(0x4c)
+      const data2 = '01'.repeat(0x100)
+      const data3 = '01'.repeat(0x100+1)
+      const data4 = '01'.repeat(0x10000)
+      const data5 = '01'.repeat(0x10000+1)
+      const data6 = '01'.repeat(1)
+      var asm = `${data0} ${data1} ${data2} ${data3} ${data4} ${data5} ${data6}`;
+      var script = Script.fromASM(asm);
+      script.chunks[0].opcodenum.should.equal(0x4b);
+      script.chunks[1].opcodenum.should.equal(Opcode.OP_PUSHDATA1);
+      script.chunks[1].len.should.equal(0x4c);
+      script.chunks[2].opcodenum.should.equal(Opcode.OP_PUSHDATA1);
+      script.chunks[2].len.should.equal(0x100);
+      script.chunks[3].opcodenum.should.equal(Opcode.OP_PUSHDATA2);
+      script.chunks[3].len.should.equal(0x100+1);
+      script.chunks[4].opcodenum.should.equal(Opcode.OP_PUSHDATA2);
+      script.chunks[4].len.should.equal(0x10000);
+      script.chunks[5].opcodenum.should.equal(Opcode.OP_PUSHDATA4);
+      script.chunks[5].len.should.equal(0x10000+1);
+      script.chunks[6].opcodenum.should.equal(1);
+      script.chunks[6].len.should.equal(1);
+    });
   });
 
   describe('#fromString', function() {