diff --git a/pyerrors/obs.py b/pyerrors/obs.py
index 54b3109c..6b25b723 100644
--- a/pyerrors/obs.py
+++ b/pyerrors/obs.py
@@ -12,6 +12,9 @@ import numdifftools as nd
 from itertools import groupby
 from .covobs import Covobs
 
+# Improve print output of numpy.ndarrays containing Obs objects.
+np.set_printoptions(formatter={'object': lambda x: str(x)})
+
 
 class Obs:
     """Class for a general observable.