diff --git a/client.c b/client.c
index 3993ed815..bec530aa6 100644
--- a/client.c
+++ b/client.c
@@ -549,6 +549,7 @@ client_manage(xcb_window_t w, xcb_get_geometry_reply_t *wgeom, int phys_screen,
     property_update_wm_transient_for(c, NULL);
     property_update_wm_client_leader(c, NULL);
     property_update_wm_client_machine(c);
+    property_update_net_wm_pid(c, NULL);
 
     /* Then check clients hints */
     ewmh_client_check_hints(c);
@@ -1633,9 +1634,6 @@ luaA_client_index(lua_State *L)
     client_t *c = luaA_client_checkudata(L, 1);
     const char *buf = luaL_checklstring(L, 2, &len);
     char *value;
-    void *data;
-    xcb_get_property_cookie_t prop_c;
-    xcb_get_property_reply_t *prop_r = NULL;
     double d;
 
     if(luaA_usemetatable(L, 1, 2))
@@ -1714,16 +1712,7 @@ luaA_client_index(lua_State *L)
         p_delete(&value);
         break;
       case A_TK_PID:
-        prop_c = xcb_get_property_unchecked(globalconf.connection, false, c->win, _NET_WM_PID, CARDINAL, 0L, 1L);
-        prop_r = xcb_get_property_reply(globalconf.connection, prop_c, NULL);
-
-        if(prop_r && prop_r->value_len && (data = xcb_get_property_value(prop_r)))
-            lua_pushnumber(L, *(uint32_t *)data);
-        else
-        {
-            p_delete(&prop_r);
-            return 0;
-        }
+        lua_pushnumber(L, c->pid);
         break;
       case A_TK_ID:
         lua_pushnumber(L, c->win);
diff --git a/client.h b/client.h
index d0d98736b..ae165d76e 100644
--- a/client.h
+++ b/client.h
@@ -150,6 +150,8 @@ struct client_t
     bool size_hints_honor;
     /** Machine the client is running on. */
     char *machine;
+    /** Client pid */
+    uint32_t pid;
     /** Window it is transient for */
     client_t *transient_for;
 };
diff --git a/property.c b/property.c
index 1df965f41..1c37705a3 100644
--- a/property.c
+++ b/property.c
@@ -397,6 +397,46 @@ property_handle_net_wm_icon(void *data,
     return 0;
 }
 
+void
+property_update_net_wm_pid(client_t *c,
+                           xcb_get_property_reply_t *reply)
+{
+    bool no_reply = !reply;
+
+    if(no_reply)
+    {
+        xcb_get_property_cookie_t prop_c =
+            xcb_get_property_unchecked(globalconf.connection, false, c->win, _NET_WM_PID, CARDINAL, 0L, 1L);
+        reply = xcb_get_property_reply(globalconf.connection, prop_c, NULL);
+    }
+
+    if(reply && reply->value_len)
+    {
+        uint32_t *rdata = xcb_get_property_value(reply);
+        if(rdata)
+            c->pid = *rdata;
+    }
+
+    if(no_reply)
+        p_delete(&reply);
+}
+
+static int
+property_handle_net_wm_pid(void *data,
+                           xcb_connection_t *connection,
+                           uint8_t state,
+                           xcb_window_t window,
+                           xcb_atom_t name,
+                           xcb_get_property_reply_t *reply)
+{
+    client_t *c = client_getbywin(window);
+
+    if(c)
+        property_update_net_wm_pid(c, reply);
+
+    return 0;
+}
+
 /** Update the list of supported protocols for a client.
  * \param c The client.
  */
@@ -539,6 +579,8 @@ void a_xcb_set_property_handlers(void)
                              property_handle_net_wm_strut_partial, NULL);
     xcb_property_set_handler(&globalconf.prophs, _NET_WM_ICON, UINT_MAX,
                              property_handle_net_wm_icon, NULL);
+    xcb_property_set_handler(&globalconf.prophs, _NET_WM_PID, UINT_MAX,
+                             property_handle_net_wm_pid, NULL);
 
     /* background change */
     xcb_property_set_handler(&globalconf.prophs, _XROOTPMAP_ID, 1,
diff --git a/property.h b/property.h
index 9c8e09416..5f761ab6c 100644
--- a/property.h
+++ b/property.h
@@ -33,6 +33,7 @@ void property_update_wm_name(client_t *);
 void property_update_wm_icon_name(client_t *);
 void property_update_wm_protocols(client_t *);
 void property_update_wm_client_machine(client_t *);
+void property_update_net_wm_pid(client_t *, xcb_get_property_reply_t *);
 void a_xcb_set_property_handlers(void);
 
 #endif