diff --git a/tupak/prior.py b/tupak/prior.py
index d1b1a3986f8772e00a868cda3f3352c7e4c7dee0..e1f23371f5f816150411207e54ce529b33a43783 100644
--- a/tupak/prior.py
+++ b/tupak/prior.py
@@ -180,6 +180,8 @@ class Cosine(Prior):
 
     def __init__(self, name=None, latex_label=None):
         Prior.__init__(self, name, latex_label)
+        self.minimum = - np.pi / 2
+        self.maximum = np.pi / 2
 
     def rescale(self, val):
         """
@@ -203,6 +205,8 @@ class Sine(Prior):
 
     def __init__(self, name=None, latex_label=None):
         Prior.__init__(self, name, latex_label)
+        self.minimum = 0
+        self.maximum = np.pi
 
     def rescale(self, val):
         """