diff --git a/programs/games/kosilka/Tupfile.lua b/programs/games/kosilka/Tupfile.lua
index fadf6c3009..1537e945f6 100644
--- a/programs/games/kosilka/Tupfile.lua
+++ b/programs/games/kosilka/Tupfile.lua
@@ -2,8 +2,8 @@ if tup.getconfig("NO_FASM") ~= "" or tup.getconfig("NO_MSVC") ~= "" then return
 HELPERDIR = (tup.getconfig("HELPERDIR") == "") and "../.." or tup.getconfig("HELPERDIR")
 tup.include(HELPERDIR .. "/use_msvc.lua")
 if tup.getconfig("LANG") == "ru"
-then CFLAGS = CFLAGS .. " -DLANG=RUS"
-else CFLAGS = CFLAGS .. " -DLANG=ENG"
+then CFLAGS = CFLAGS .. " /DLANG=RUS"
+else CFLAGS = CFLAGS .. " /DLANG=ENG"
 end
 compile_msvc{"kosilka.cpp", "KosFile.cpp", "kosSyst.cpp", "mcsmemm.cpp"}
 link_msvc("kosilka")