diff --git a/src/transaction_builder.js b/src/transaction_builder.js
index fc6a419..c0acb09 100644
--- a/src/transaction_builder.js
+++ b/src/transaction_builder.js
@@ -34,6 +34,10 @@ TransactionBuilder.fromTransaction = function(transaction) {
     // Ignore empty scripts
     if (txin.script.buffer.length === 0) return
 
+    assert(!Array.prototype.every.call(txin.hash, function(x) {
+      return x === 0
+    }), 'coinbase inputs not supported')
+
     var redeemScript
     var scriptSig = txin.script
     var scriptType = scripts.classifyInput(scriptSig)
@@ -83,7 +87,7 @@ TransactionBuilder.fromTransaction = function(transaction) {
         break
 
       default:
-        assert(false, scriptType + ' not supported')
+        assert(false, scriptType + ' inputs not supported')
     }
 
     txb.signatures[i] = {
diff --git a/test/fixtures/transaction_builder.json b/test/fixtures/transaction_builder.json
index 6795c48..a44078b 100644
--- a/test/fixtures/transaction_builder.json
+++ b/test/fixtures/transaction_builder.json
@@ -167,6 +167,16 @@
           }
         ]
       }
+    ],
+    "fromTransaction": [
+      {
+        "exception": "coinbase inputs not supported",
+        "hex":"01000000010000000000000000000000000000000000000000000000000000000000000000000000006b483045022100a3b254e1c10b5d039f36c05f323995d6e5a367d98dd78a13d5bbc3991b35720e022022fccea3897d594de0689601fbd486588d5bfa6915be2386db0397ee9a6e80b601210279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798ffffffff0110270000000000001976a914aa4d7985c57e011a8b3dd8e0e5a73aaef41629c588ac00000000" 
+      },
+      {
+        "exception": "nonstandard inputs not supported",
+        "hex": "0100000001ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff0000000023aa206fe28c0ab6f1b372c1a6a246ae63f74f931e8365e15a089c68d619000000000087ffffffff0110270000000000001976a914aa4d7985c57e011a8b3dd8e0e5a73aaef41629c588ac00000000" 
+      }
     ]
   }
 }
diff --git a/test/transaction_builder.js b/test/transaction_builder.js
index 974f687..0bc1032 100644
--- a/test/transaction_builder.js
+++ b/test/transaction_builder.js
@@ -256,6 +256,16 @@ describe('TransactionBuilder', function() {
       })
     })
 
+    fixtures.invalid.fromTransaction.forEach(function(f,i) {
+      it('throws on ' + f.exception, function() {
+        var tx = Transaction.fromHex(f.hex)
+
+        assert.throws(function() {
+          TransactionBuilder.fromTransaction(tx)
+        }, new RegExp(f.exception))
+      })
+    })
+
     it('works for the P2SH multisig case', function() {
       var privKeys = [
         "91avARGdfge8E4tZfYLoxeJ5sGBdNJQH4kvjJoQFacbgwmaKkrx",