diff --git a/README.markdown b/README.markdown
index 81edb8e..22cba49 100644
--- a/README.markdown
+++ b/README.markdown
@@ -30,3 +30,6 @@ becomes
 	* [x] Do some work.
 
 and vice versa.
+
+If there is nothing to toggle a checkbox is added to the beginning of
+the current line.
diff --git a/plugin/checkbox.vim b/plugin/checkbox.vim
index 8c853b3..194f0eb 100644
--- a/plugin/checkbox.vim
+++ b/plugin/checkbox.vim
@@ -23,6 +23,8 @@ fu! checkbox#ToggleCB()
 		let line = substitute(line, "\\[ \\]", "[x]", "")
 	elseif(match(line, "\\[x\\]") != -1)
 		let line = substitute(line, "\\[x\\]", "[ ]", "")
+	else
+		let line = substitute(line, "^", "[ ] ", "")
 	endif
 
 	call setline('.', line)