diff --git a/core/sys_config.inc.php b/core/sys_config.inc.php
index 4190358f..c70acb93 100644
--- a/core/sys_config.inc.php
+++ b/core/sys_config.inc.php
@@ -35,6 +35,7 @@ _d("NICE_URLS", false);      // boolean  force niceurl mode
 _d("WH_SPLITS", 1);          // int      how many levels of subfolders to put in the warehouse
 _d("VERSION", 'trunk');      // string   shimmie version
 _d("TIMEZONE", null);        // string   timezone
+_d("MIN_FREE_SPACE",100*1024*1024); // int      disable uploading if there's less than MIN_FREE_SPACE bytes free space
 _d("CORE_EXTS", "bbcode,user,mail,upload,image,view,handle_pixel,ext_manager,setup,upgrade,handle_404,comment,tag_list,index,tag_edit,alias_editor"); // extensions to always enable
 _d("EXTRA_EXTS", "");        // optional extra extensions
 
diff --git a/ext/upload/main.php b/ext/upload/main.php
index 9c92cb19..2e7a073e 100644
--- a/ext/upload/main.php
+++ b/ext/upload/main.php
@@ -56,9 +56,7 @@ class Upload extends Extension {
 			$this->is_full = false;
 		}
 		else {
-			// TODO: This size limit should be configureable by the admin...
-			// currently set to 100 MB
-			$this->is_full = $free_num < 100*1024*1024;
+			$this->is_full = $free_num < MIN_FREE_SPACE;
 		}
 
 	}