diff --git a/lib/driver/pg.js b/lib/driver/pg.js
index <HASH>..<HASH> 100644
--- a/lib/driver/pg.js
+++ b/lib/driver/pg.js
@@ -131,7 +131,7 @@ var PgDriver = Base.extend({
           if (typeof columnSpec.defaultValue == 'string'){
             defaultValue = "'" + columnSpec.defaultValue + "'";
           } else {
-            defaultValue = spec.defaultValue;
+            defaultValue = columnSpec.defaultValue;
           }
           sql = util.format("ALTER TABLE %s ALTER COLUMN %s SET DEFAULT %s", tableName, columnName, defaultValue);
         } else {
change 'spec' to 'columnSpec' in setDefaultValue() because 'spec' is not defined in that scope