diff --git a/src/opatIO/private/opatIO.cpp b/src/opatIO/private/opatIO.cpp
index 9c3b043..6ae7f37 100644
--- a/src/opatIO/private/opatIO.cpp
+++ b/src/opatIO/private/opatIO.cpp
@@ -10,6 +10,7 @@
 #include <cmath>
 #include <limits>
 #include <deque>
+#include <cstdint>
 #include "picosha2.h"
 
 // Function to check system endianness
diff --git a/src/opatIO/public/opatIO.h b/src/opatIO/public/opatIO.h
index 5fdad3f..1e816d4 100644
--- a/src/opatIO/public/opatIO.h
+++ b/src/opatIO/public/opatIO.h
@@ -8,6 +8,7 @@
 #include <deque>
 #include <map>
 #include <utility>
+#include <cstdint>
 
 /**
  * @brief Structure to hold the header information of an OPAT file.