diff --git a/Changes b/Changes
index beb5043..ed2e8ff 100644
--- a/Changes
+++ b/Changes
@@ -11,6 +11,7 @@
         - Optimization by reducing calls to _offset().
         - Introduced add_span() method to MultiTermToken.
         - Removed deprecated 'primary' flag.
+        - Removed deprecated 'pretty' flag.
 
 0.40 2020-03-03
         - Fixed XIP parser.
diff --git a/lib/KorAP/XML/Batch/File.pm b/lib/KorAP/XML/Batch/File.pm
index 6dc5d7b..5c1bea9 100644
--- a/lib/KorAP/XML/Batch/File.pm
+++ b/lib/KorAP/XML/Batch/File.pm
@@ -22,7 +22,6 @@
     koral           => $param{koral},
     non_word_tokens => $param{non_word_tokens},
     non_verbal_tokens => $param{non_verbal_tokens},
-    pretty          => $param{pretty},
     gzip            => $param{gzip}      // 0
   }, $class;
 };
@@ -73,11 +72,7 @@
   };
 
   my $file;
-  my $print_text = (
-    $self->{pretty} ?
-      $tokens->to_pretty_json($self->{koral}) :
-      $tokens->to_json($self->{koral})
-    );
+  my $print_text = $tokens->to_json($self->{koral});
 
   # There is an output file given
   if ($output) {
@@ -200,11 +195,6 @@
 
 A L<Mojo::Log> compatible log object.
 
-=item pretty
-
-Pretty print the output JSON.
-Defaults to C<false>.
-
 =item gzip
 
 Compress the output using Gzip.
diff --git a/lib/KorAP/XML/Tokenizer.pm b/lib/KorAP/XML/Tokenizer.pm
index ffd9f80..7e72968 100644
--- a/lib/KorAP/XML/Tokenizer.pm
+++ b/lib/KorAP/XML/Tokenizer.pm
@@ -608,13 +608,6 @@
   encode_json($self->to_data($version));
 };
 
-
-sub to_pretty_json {
-  my ($self, $version) = @_;
-  JSON::XS->new->pretty->encode($self->to_data($version));
-};
-
-
 # Remove diacritics from a unicode string
 sub remove_diacritics {
   use utf8;
diff --git a/script/korapxml2krill b/script/korapxml2krill
index 791d115..b42c793 100644
--- a/script/korapxml2krill
+++ b/script/korapxml2krill
@@ -196,7 +196,9 @@
   'primary|p!'  => sub {
     warn 'Primary flag no longer supported!';
   },
-  'pretty|y'    => \(my $pretty),
+  'pretty|y'    => sub {
+    warn 'Pretty flag no longer supported!';
+  },
   'jobs|j=i'    => \($cfg{jobs}),
   'koral|k=f'    => \($cfg{koral}),
   'to-tar'      => \($cfg{to_tar}),
@@ -502,7 +504,6 @@
   gzip      => $gzip,
   log       => $log,
   koral     => ($cfg{koral} // $KORAL_VERSION),
-  pretty    => $pretty,
   anno      => \@filtered_anno,
   non_word_tokens   => ($cfg{non_word_tokens}   // 0),
   non_verbal_tokens => ($cfg{non_verbal_tokens} // 0)
@@ -1211,12 +1212,6 @@
 This is I<experimental>.
 
 
-=item B<--pretty|-y>
-
-Pretty print JSON output. Defaults to C<false>.
-This is I<deprecated>.
-
-
 =item B<--gzip|-z>
 
 Compress the output.
diff --git a/t/batch_file.t b/t/batch_file.t
index 12f7e12..55f4631 100644
--- a/t/batch_file.t
+++ b/t/batch_file.t
@@ -105,13 +105,6 @@
 
 like($file, qr/^\{"/, 'No pretty printing');
 
-# Check pretty printing
-$bf->{pretty} = 1;
-ok($bf->process($path => $output), 'Process file');
-ok(-f $output, 'File exists');
-ok($file = Mojo::File->new($output)->slurp, 'Slurp data');
-like($file, qr/^\{[\n\s]+"/, 'No pretty printing');
-
 # Check overwriting
 $bf->{overwrite} = 0;