diff --git a/lib/TransactionDb.js b/lib/TransactionDb.js
index e5ac6ee..3f04331 100644
--- a/lib/TransactionDb.js
+++ b/lib/TransactionDb.js
@@ -380,7 +380,7 @@ function spec(b) {
         async.forEachLimit(tx.vin, CONCURRENCY,
           function(i, next_out) {
             db.batch()
-              .put( SPEND_PREFIX  + i.txid + '-' + i.vout + '-' +  tx.txid + '-' + i.n, ts)
+              .put( SPEND_PREFIX  + i.txid + '-' + i.vout + '-' +  tx.txid + '-' + i.n, ts || 0)
               .write(next_out);
           },
           function (err) {