diff --git a/plugin/textobj/underscore.vim b/plugin/textobj/underscore.vim
index 85ba71d..0d60df0 100644
--- a/plugin/textobj/underscore.vim
+++ b/plugin/textobj/underscore.vim
@@ -10,29 +10,54 @@ call textobj#user#plugin('underscore', {
 \      }
 \    })
 
+" Start Pos:
+" 1. "_" ("foo[_]bar[_]baz")
+" word character after
+" 2. [:space:] ("  [f]oo_bar_baz")
+" 3. ^ ("[f]oo_bar_baz")
+" 4. \W (":[s]mile:")
+"
+" End Pos:
+" 1. "_" ("foo[_]bar[_]baz")
+" word character before
+" 2. [:space:] ("foo_bar_ba[z]  ")
+" 3. $ ("foo_bar_ba[z]")
+" 4. \W (":smil[e]:")
 function! s:select_a()
-  normal! F_
+  let pattern = '\%' . line('.') . 'l\%(_\|\%([[:space:]]\|^\|\W\)\zs\w\)'
+  call search(pattern, 'bcW')
+  let start_pos = getpos('.')
 
+  let pattern = '\%' . line('.') . 'l\%(_\|\w\ze\%([[:space:]]\|$\|\W\)\)'
+  call search(pattern, 'W')
   let end_pos = getpos('.')
 
-  normal! f_
-
-  let start_pos = getpos('.')
-  return ['v', start_pos, end_pos]
+  return (start_pos ==# end_pos ? 0 : ['v', start_pos, end_pos])
 endfunction
 
-" ciao_come_stai
-
+" Start Pos:
+" word character after
+" 1. "_" ("foo_[b]ar_[b]az")
+" 2. [:space:] ("  [f]oo_bar_baz")
+" 3. ^ ("[f]oo_bar_baz")
+" 4. \W (":[s]mile:")
+"
+" End Pos:
+" word character before
+" 1. "_" ("fo[o]_ba[r]_baz")
+" 2. [:space:] ("foo_bar_ba[z]  ")
+" 3. $ ("foo_bar_ba[z]")
+" 4. \W (":smil[e]:")
 function! s:select_i()
-  normal! T_
+  let pattern = '\%' . line('.') . 'l\%([_[:space:]]\|^\|\W\)\zs\w'
+  call search(pattern, 'bcW')
+  let start_pos = getpos('.')
 
+  let pattern = '\%' . line('.') . 'l\w\ze\%([_[:space:]]\|$\|\W\)'
+  call search(pattern, 'cW')
   let end_pos = getpos('.')
 
-  normal! t_
-
-  let start_pos = getpos('.')
-
-  return ['v', start_pos, end_pos]
+  return (start_pos ==# end_pos ? 0 : ['v', start_pos, end_pos])
 endfunction
 
 let g:loaded_textobj_underscore = 1