diff --git a/prelude/base.v b/prelude/base.v
index 8f01258a121363b1fab7f29949b8ae6957fb2800..c097a713a84be653b8378b01fc677331f7c49d2d 100644
--- a/prelude/base.v
+++ b/prelude/base.v
@@ -375,8 +375,6 @@ Notation zip := (zip_with pair).
 Coercion Is_true : bool >-> Sortclass.
 Hint Unfold Is_true.
 Hint Immediate Is_true_eq_left.
-Existing Class Is_true.
-Instance true_Is_true : Is_true true := I.
 Hint Resolve orb_prop_intro andb_prop_intro.
 Notation "(&&)" := andb (only parsing).
 Notation "(||)" := orb (only parsing).