diff --git a/src/main/scala/leon/purescala/PrettyPrinter.scala b/src/main/scala/leon/purescala/PrettyPrinter.scala
index 02acab8d15ff0e60aaa507392f765501563cc3ee..8c24c9a9049c7f482e7240922a116795f48d9e33 100644
--- a/src/main/scala/leon/purescala/PrettyPrinter.scala
+++ b/src/main/scala/leon/purescala/PrettyPrinter.scala
@@ -402,7 +402,7 @@ class PrettyPrinter(opts: PrinterOptions,
 
       // Definitions
       case Program(units) =>
-        p"""${nary(units filter { _.isMainUnit }, "\n\n")}"""
+        p"""${nary(units filter { opts.printUniqueIds || _.isMainUnit }, "\n\n")}"""
 
       case UnitDef(id,pack, imports, defs,_) =>
         if (pack.nonEmpty){