diff --git a/src/os/osf1/sigar_os.h b/src/os/osf1/sigar_os.h
index 068fc3c6..46674deb 100644
--- a/src/os/osf1/sigar_os.h
+++ b/src/os/osf1/sigar_os.h
@@ -1,6 +1,12 @@
 #ifndef SIGAR_OS_H
 #define SIGAR_OS_H
 
+#include <sys/vm.h>
+
+#include <mach.h>
+#include <mach/mach_types.h>
+#include <mach/vm_statistics.h>
+
 struct sigar_t {
     SIGAR_T_BASE;
 };