diff --git a/awesomerc.1.txt b/awesomerc.1.txt
index 388c5b29..16d8a809 100644
--- a/awesomerc.1.txt
+++ b/awesomerc.1.txt
@@ -512,6 +512,7 @@ rules
         screen = <integer>
         icon = <image>
         not_master = <boolean>
+        opacity = <float>
     }
 }
 keys
diff --git a/client.c b/client.c
index 973c98e5..9f96531e 100644
--- a/client.c
+++ b/client.c
@@ -285,6 +285,9 @@ client_manage(Window w, XWindowAttributes *wa, int screen)
                 client_setfloating(c, False);
                 break;
             }
+
+            if(rule->opacity >= 0.0f)
+                window_settrans(c->win, rule->opacity);
         }
         else
             move_client_to_screen(c, screen, True);
diff --git a/config.c b/config.c
index 4eb0e023..6afb6511 100644
--- a/config.c
+++ b/config.c
@@ -644,6 +644,7 @@ config_parse(const char *confpatharg)
         CFG_STR((char *) "float", (char *) "auto", CFGF_NONE),
         CFG_INT((char *) "screen", RULE_NOSCREEN, CFGF_NONE),
         CFG_BOOL((char *) "not_master", cfg_false, CFGF_NONE),
+        CFG_FLOAT((char *) "opacity", -1.0f, CFGF_NONE),
         CFG_END()
     };
     static cfg_opt_t rules_opts[] =
@@ -756,6 +757,7 @@ config_parse(const char *confpatharg)
         rule->isfloating = rules_get_float_from_str(cfg_getstr(cfgsectmp, "float"));
         rule->screen = cfg_getint(cfgsectmp, "screen");
         rule->not_master = cfg_getbool(cfgsectmp, "not_master");
+        rule->opacity = cfg_getfloat(cfgsectmp, "opacity");
         if(rule->screen >= globalconf.nscreen)
             rule->screen = 0;
 
diff --git a/structs.h b/structs.h
index 60f30882..9821a57f 100644
--- a/structs.h
+++ b/structs.h
@@ -61,6 +61,7 @@ struct Rule
     int screen;
     RuleFloat isfloating;
     Bool not_master;
+    double opacity;
     regex_t *prop_r;
     regex_t *tags_r;
     regex_t *xpropval_r;