diff --git a/artiq/protocols/pyon.py b/artiq/protocols/pyon.py
index 3ddef16a9..2ad6755fd 100644
--- a/artiq/protocols/pyon.py
+++ b/artiq/protocols/pyon.py
@@ -193,6 +193,7 @@ _eval_dict = {
     "null": None,
     "false": False,
     "true": True,
+    "inf": numpy.inf,
     "slice": slice,
     "nan": numpy.nan,