diff --git a/configure.ac b/configure.ac
index 51e35a8..e92b602 100644
--- a/configure.ac
+++ b/configure.ac
@@ -22,6 +22,11 @@ case $host_os in
 		HOST_ABI=elf
 		AC_SUBST([PROG_LDADD], ['-lthr'])
 		;;
+	*hpux*)
+		HOST_OS=hpux;
+		CFLAGS="$CFLAGS -mlp64 -D_XOPEN_SOURCE=600 -D__STRICT_ALIGNMENT"
+		AC_SUBST([PLATFORM_LDADD], ['-lpthread'])
+		;;
 	*linux*)
 		HOST_OS=linux
 		HOST_ABI=elf
@@ -53,6 +58,7 @@ esac
 
 AM_CONDITIONAL([HOST_DARWIN],  [test x$HOST_OS = xdarwin])
 AM_CONDITIONAL([HOST_FREEBSD], [test x$HOST_OS = xfreebsd])
+AM_CONDITIONAL([HOST_HPUX],    [test x$HOST_OS = xhpux])
 AM_CONDITIONAL([HOST_LINUX],   [test x$HOST_OS = xlinux])
 AM_CONDITIONAL([HOST_SOLARIS], [test x$HOST_OS = xsolaris])
 AM_CONDITIONAL([HOST_WIN],     [test x$HOST_OS = xwin])
diff --git a/crypto/Makefile.am b/crypto/Makefile.am
index e5a4d4d..9f5311a 100644
--- a/crypto/Makefile.am
+++ b/crypto/Makefile.am
@@ -86,6 +86,9 @@ endif
 if HOST_WIN
 libcompat_la_SOURCES += compat/getentropy_win.c
 endif
+if HOST_HPUX
+libcompat_la_SOURCES += compat/getentropy_hpux.c
+endif
 endif
 
 endif
@@ -97,6 +100,9 @@ endif
 if HOST_WIN
 libcompat_la_SOURCES += compat/issetugid_win.c
 endif
+if HOST_HPUX
+libcompat_la_SOURCES += compat/issetugid_hpux.c
+endif
 endif
 
 noinst_HEADERS =
@@ -106,6 +112,7 @@ noinst_HEADERS += compat/arc4random_linux.h
 noinst_HEADERS += compat/arc4random_osx.h
 noinst_HEADERS += compat/arc4random_solaris.h
 noinst_HEADERS += compat/arc4random_win.h
+noinst_HEADERS += compat/arc4random_hpux.h
 noinst_HEADERS += compat/chacha_private.h
 
 libcrypto_la_SOURCES =
diff --git a/crypto/compat/arc4random.h b/crypto/compat/arc4random.h
index 53b5a46..ed812ba 100644
--- a/crypto/compat/arc4random.h
+++ b/crypto/compat/arc4random.h
@@ -6,6 +6,9 @@
 #if defined(__FreeBSD__)
 #include "arc4random_freebsd.h"
 
+#elif defined(__hpux)
+#include "arc4random_hpux.h"
+
 #elif defined(__linux__)
 #include "arc4random_linux.h"
 
diff --git a/crypto/compat/issetugid_hpux.c b/crypto/compat/issetugid_hpux.c
new file mode 100644
index 0000000..73def9b
--- /dev/null
+++ b/crypto/compat/issetugid_hpux.c
@@ -0,0 +1,26 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/pstat.h>
+
+/*
+ * HP-UX does not have issetugid().
+ * This experimental implementation uses pstat_getproc() and get*id().
+ * First, try pstat_getproc() and check PS_CHANGEDPRIV bit of pst_flag. 
+ * In case unsuccessful calling pstat_getproc(), using get*id().
+ *
+ */
+int issetugid(void)
+{
+	struct pst_status buf;
+	if(pstat_getproc(&buf, sizeof(buf), 0, getpid()) != 1) {
+	    perror("pstat_getproc()");
+	} else {
+	    if(buf.pst_flag & PS_CHANGEDPRIV)
+		return 1;
+	}
+	if(getuid() != geteuid())
+	    return 1;
+	if(getgid() != getegid())
+	    return 1;
+	return 0;
+}