diff --git a/specs/udmf_zdoom.txt b/specs/udmf_zdoom.txt
index 0fe7b1e8e..112e54bfc 100644
--- a/specs/udmf_zdoom.txt
+++ b/specs/udmf_zdoom.txt
@@ -224,13 +224,11 @@ Note: All <bool> fields default to false unless mentioned otherwise.
 	                                  // 0 meaning that the default is to be used, 2 equalling the density of a light level of 250, and 255 equalling the density of
 	                                  // a light level of 0.
 
-      portal_ceil_alpha = <float>     // translucency of ceiling portal (default is 0 (not visible))
       portal_ceil_blocksound = <bool> // ceiling portal blocks sound.
       portal_ceil_disabled = <bool>   // ceiling portal disabled.
       portal_ceil_nopass = <bool>     // ceiling portal blocks movement if true.
       portal_ceil_norender = <bool>   // ceiling portal not rendered.
       portal_ceil_overlaytype = <string> // defines translucency style, can either be "translucent" or "additive". Default is "translucent".
-      portal_floor_alpha = <float>     // translucency of floor portal (default is 0 (not visible))
       portal_floor_blocksound = <bool> // floor portal blocks sound.
       portal_floor_disabled = <bool>   // floor portal disabled.
       portal_floor_nopass = <bool>     // ceiling portal blocks movement if true.
diff --git a/src/namedef.h b/src/namedef.h
index bb9d27f40..d50f8131d 100644
--- a/src/namedef.h
+++ b/src/namedef.h
@@ -518,14 +518,12 @@ xx(Alphaceiling)
 xx(Renderstylefloor)
 xx(Renderstyleceiling)
 xx(Waterzone)
-xx(portal_ceil_alpha)
 xx(portal_ceil_blocksound)
 xx(portal_ceil_disabled)
 xx(portal_ceil_nopass)
 xx(portal_ceil_norender)
 xx(portal_ceil_overlaytype)
 xx(portal_ceil_useglobaltex)
-xx(portal_floor_alpha)
 xx(portal_floor_blocksound)
 xx(portal_floor_disabled)
 xx(portal_floor_nopass)
diff --git a/src/p_udmf.cpp b/src/p_udmf.cpp
index b0427045c..461feb9c8 100644
--- a/src/p_udmf.cpp
+++ b/src/p_udmf.cpp
@@ -1582,10 +1582,6 @@ public:
 					tagstring = CheckString(key);
 					break;
 
-				case NAME_portal_ceil_alpha:
-					sec->planes[sector_t::ceiling].alpha = CheckFloat(key);
-					break;
-
 				case NAME_portal_ceil_blocksound:
 					Flag(sec->planes[sector_t::ceiling].Flags, PLANEF_BLOCKSOUND, key);
 					break;
@@ -1607,10 +1603,6 @@ public:
 					else if (!stricmp(CheckString(key), "additive")) sec->planes[sector_t::ceiling].Flags |= PLANEF_ADDITIVE;
 					break;
 				
-				case NAME_portal_floor_alpha:
-					sec->planes[sector_t::floor].alpha = CheckFloat(key);
-					break;
-
 				case NAME_portal_floor_blocksound:
 					Flag(sec->planes[sector_t::floor].Flags, PLANEF_BLOCKSOUND, key);
 					break;