diff --git a/src/Persistent_cohomology/include/gudhi/Persistent_cohomology.h b/src/Persistent_cohomology/include/gudhi/Persistent_cohomology.h
index 084bf177d8..47364edfc3 100644
--- a/src/Persistent_cohomology/include/gudhi/Persistent_cohomology.h
+++ b/src/Persistent_cohomology/include/gudhi/Persistent_cohomology.h
@@ -19,6 +19,7 @@
 #include <boost/pending/disjoint_sets.hpp>
 #include <boost/intrusive/list.hpp>
 
+#include <iostream>
 #include <map>
 #include <unordered_map>
 #include <utility>