diff --git a/python.jam b/python.jam
index fd4035ba2..d3803299f 100644
--- a/python.jam
+++ b/python.jam
@@ -114,7 +114,8 @@ CYGWIN_ROOT ?= c:/cygwin ;
     
     for d in "" _D
     {
-        local debug = $(d)EBUG ;
+        local d_D = _DEBUG ;
+        local debug = $(d$(d)) ; # "" or _DEBUG
 
         # select target description variable
         local var = CYGWIN_PYTHON$(d) ; 
diff --git a/v1/python.jam b/v1/python.jam
index fd4035ba2..d3803299f 100644
--- a/v1/python.jam
+++ b/v1/python.jam
@@ -114,7 +114,8 @@ CYGWIN_ROOT ?= c:/cygwin ;
     
     for d in "" _D
     {
-        local debug = $(d)EBUG ;
+        local d_D = _DEBUG ;
+        local debug = $(d$(d)) ; # "" or _DEBUG
 
         # select target description variable
         local var = CYGWIN_PYTHON$(d) ;