diff --git a/kibot/out_position.py b/kibot/out_position.py
index 71df3698..3de348e9 100644
--- a/kibot/out_position.py
+++ b/kibot/out_position.py
@@ -31,6 +31,12 @@ def _ref_key(ref_str):
     return [pre, 0 if suf == '?' else int(suf)]
 
 
+def check_names(top, bot):
+    if top == bot:
+        raise KiPlotConfigurationError("Asking for two separated files, but both with the same name.\n"
+                                       "Try using %i in the name.")
+
+
 class PosColumns(Optionable):
     """ Which columns we want and its names """
     def __init__(self):
@@ -98,8 +104,11 @@ class PositionOptions(VariantOptions):
         botf = None
         bothf = None
         if self.separate_files_for_front_and_back:
-            topf = open(self.expand_filename(output_dir, self.output, 'top_pos', 'pos'), 'w')
-            botf = open(self.expand_filename(output_dir, self.output, 'bottom_pos', 'pos'), 'w')
+            topf_name = self.expand_filename(output_dir, self.output, 'top_pos', 'pos')
+            botf_name = self.expand_filename(output_dir, self.output, 'bottom_pos', 'pos')
+            check_names(topf_name, botf_name)
+            topf = open(topf_name, 'w')
+            botf = open(botf_name, 'w')
         else:
             bothf = open(self.expand_filename(output_dir, self.output, 'both_pos', 'pos'), 'w')
 
@@ -156,8 +165,11 @@ class PositionOptions(VariantOptions):
         botf = None
         bothf = None
         if self.separate_files_for_front_and_back:
-            topf = open(self.expand_filename(output_dir, self.output, 'top_pos', 'csv'), 'w')
-            botf = open(self.expand_filename(output_dir, self.output, 'bottom_pos', 'csv'), 'w')
+            topf_name = self.expand_filename(output_dir, self.output, 'top_pos', 'csv')
+            botf_name = self.expand_filename(output_dir, self.output, 'bottom_pos', 'csv')
+            check_names(topf_name, botf_name)
+            topf = open(topf_name, 'w')
+            botf = open(botf_name, 'w')
         else:
             bothf = open(self.expand_filename(output_dir, self.output, 'both_pos', 'csv'), 'w')
 
diff --git a/tests/test_plot/test_position.py b/tests/test_plot/test_position.py
index 4927208b..59df90b2 100644
--- a/tests/test_plot/test_position.py
+++ b/tests/test_plot/test_position.py
@@ -19,6 +19,7 @@ pytest-3 --log-cli-level debug
 """
 import os
 import logging
+from kibot.misc import EXIT_BAD_CONFIG
 from . import context
 
 POS_DIR = 'positiondir'
@@ -271,3 +272,10 @@ def test_position_rot_bottom(test_dir):
     ctx.expect_out_file(pos_bot)
     expect_position(ctx, pos_bot, ['U1'], neg_x=True)
     ctx.clean_up()
+
+
+def test_position_error_same_name(test_dir):
+    ctx = context.TestContext(test_dir, '3Rs', 'error_position_same_name', POS_DIR)
+    ctx.run(EXIT_BAD_CONFIG)
+    ctx.search_err(r"(.*)but both with the same name")
+    ctx.clean_up()
diff --git a/tests/yaml_samples/error_position_same_name.kibot.yaml b/tests/yaml_samples/error_position_same_name.kibot.yaml
new file mode 100644
index 00000000..8fdeba00
--- /dev/null
+++ b/tests/yaml_samples/error_position_same_name.kibot.yaml
@@ -0,0 +1,15 @@
+# Example KiBot config file for a basic 2-layer board
+kibot:
+  version: 1
+
+outputs:
+
+  - name: 'position'
+    type: position
+    dir: positiondir
+    options:
+      output: '%f.%x'
+      format: CSV   # CSV or ASCII format
+      units: millimeters  # millimeters or inches
+      separate_files_for_front_and_back: true
+      only_smd: true