diff --git a/Detectors/HMPID/base/include/HMPIDBase/Geo.h b/Detectors/HMPID/base/include/HMPIDBase/Geo.h
index c1f9fb658b0f0..d2af8d6527504 100644
--- a/Detectors/HMPID/base/include/HMPIDBase/Geo.h
+++ b/Detectors/HMPID/base/include/HMPIDBase/Geo.h
@@ -18,6 +18,7 @@
 #define ALICEO2_HMPID_GEO_H
 
 #include <TMath.h>
+#include <Rtypes.h>
 
 namespace o2
 {