diff --git a/resources/systems/macos/es_systems.xml b/resources/systems/macos/es_systems.xml
index ccc24e37f..b4d004b05 100644
--- a/resources/systems/macos/es_systems.xml
+++ b/resources/systems/macos/es_systems.xml
@@ -159,7 +159,7 @@
         <name>atari800</name>
         <fullname>Atari 800</fullname>
         <path>%ROMPATH%/atari800</path>
-        <extension>.xfd .XFD .atr .ATR .atx .ATX .cdm .CDM .cas .CAS .bin .BIN .a52 .A52 .xex .XEX .7z .7Z .zip .ZIP</extension>
+        <extension>.xfd .XFD .atr .ATR .atx .ATX .cdm .CDM .cas .CAS .bin .BIN .a52 .A52 .xex .XEX .rom .ROM .7z .7Z .zip .ZIP</extension>
         <command>%EMULATOR_RETROARCH% -L %CORE_RETROARCH%/atari800_libretro.dylib %ROM%</command>
         <platform>atari800</platform>
         <theme>atari800</theme>
diff --git a/resources/systems/unix/es_systems.xml b/resources/systems/unix/es_systems.xml
index 4647cdd2e..c353c3fc5 100644
--- a/resources/systems/unix/es_systems.xml
+++ b/resources/systems/unix/es_systems.xml
@@ -160,7 +160,7 @@
         <name>atari800</name>
         <fullname>Atari 800</fullname>
         <path>%ROMPATH%/atari800</path>
-        <extension>.xfd .XFD .atr .ATR .atx .ATX .cdm .CDM .cas .CAS .bin .BIN .a52 .A52 .xex .XEX .7z .7Z .zip .ZIP</extension>
+        <extension>.xfd .XFD .atr .ATR .atx .ATX .cdm .CDM .cas .CAS .bin .BIN .a52 .A52 .xex .XEX .rom .ROM .7z .7Z .zip .ZIP</extension>
         <command>%EMULATOR_RETROARCH% -L %CORE_RETROARCH%/atari800_libretro.so %ROM%</command>
         <platform>atari800</platform>
         <theme>atari800</theme>
diff --git a/resources/systems/windows/es_systems.xml b/resources/systems/windows/es_systems.xml
index a0d38eea9..c96f6b755 100644
--- a/resources/systems/windows/es_systems.xml
+++ b/resources/systems/windows/es_systems.xml
@@ -160,7 +160,7 @@
         <name>atari800</name>
         <fullname>Atari 800</fullname>
         <path>%ROMPATH%\atari800</path>
-        <extension>.xfd .XFD .atr .ATR .atx .ATX .cdm .CDM .cas .CAS .bin .BIN .a52 .A52 .xex .XEX .7z .7Z .zip .ZIP</extension>
+        <extension>.xfd .XFD .atr .ATR .atx .ATX .cdm .CDM .cas .CAS .bin .BIN .a52 .A52 .xex .XEX .rom .ROM .7z .7Z .zip .ZIP</extension>
         <command>%EMULATOR_RETROARCH% -L %CORE_RETROARCH%\atari800_libretro.dll %ROM%</command>
         <platform>atari800</platform>
         <theme>atari800</theme>