diff --git a/lib/rouge/demos/gdt b/lib/rouge/demos/gdt
new file mode 100644
index 0000000000..6cdc759f21
--- /dev/null
+++ b/lib/rouge/demos/gdt
@@ -0,0 +1,11 @@
+01380006301
+0178315EKG_TYP1
+0178316PRX_SYS1
+014921802.00
+01330000815
+0123101Doe
+0133102Jane
+017310301011990
+01031102
+0123622158
+0123623061
\ No newline at end of file
diff --git a/lib/rouge/lexers/gdt.rb b/lib/rouge/lexers/gdt.rb
new file mode 100644
index 0000000000..4c84fb403a
--- /dev/null
+++ b/lib/rouge/lexers/gdt.rb
@@ -0,0 +1,41 @@
+# -*- coding: utf-8 -*- #
+# frozen_string_literal: true
+
+module Rouge
+  module Lexers
+    class GDT < RegexLexer
+      title 'GDT'
+      desc "Geräte-Daten-Träger (Device Data Carrier)"
+      tag 'gdt'
+      filenames '*.gdt'
+      mimetypes 'text/x-gdt'
+
+      state :root do
+        rule %r/[0-9]{3}/, Text, :length
+      end
+
+      state :length do
+        rule %r/(6227|6228)/, Keyword, :comment
+        rule %r/8000/, Keyword, :type
+        rule %r/[0-9]{4}/, Keyword, :content
+        rule %r/\s+/, Text::Whitespace
+      end
+
+      state :content do
+        rule %r/.*$\r?\n?/, Literal, :root
+      end
+
+      state :comment do
+        rule %r/.*$\r?\n?/, Comment, :root
+      end
+
+      state :type do
+        rule %r/.*$\r?\n?/, Name::Class, :root
+      end
+
+      state :whitespace do
+        rule %r/\s+/, Text::Whitespace
+      end
+    end
+  end
+end
diff --git a/spec/lexers/gdt_spec.rb b/spec/lexers/gdt_spec.rb
new file mode 100644
index 0000000000..d23508c296
--- /dev/null
+++ b/spec/lexers/gdt_spec.rb
@@ -0,0 +1,18 @@
+# -*- coding: utf-8 -*- #
+# frozen_string_literal: true
+
+describe Rouge::Lexers::GDT do
+  let(:subject) { Rouge::Lexers::GDT.new }
+
+  describe 'guessing' do
+    include Support::Guessing
+
+    it 'guesses by filename' do
+      assert_guess :filename => 'foo.gdt'
+    end
+
+    it 'guesses by mimetype' do
+      assert_guess :mimetype => 'text/x-gdt'
+    end
+  end
+end
diff --git a/spec/visual/samples/gdt b/spec/visual/samples/gdt
new file mode 100644
index 0000000000..c1b78f2fbb
--- /dev/null
+++ b/spec/visual/samples/gdt
@@ -0,0 +1,19 @@
+01380006310
+0178315PRX_SYS1
+0178316KKX_SYS1
+014921802.10
+014300004711
+0123101Doe
+0133102John
+017310331121999
+01031101
+0123622180
+0123623085
+017620031122023
+0166227Comment
+0286228Blood pressure test
+0286228-------------------
+0236228Ps[mmHg]   143
+0236228Pd[mmHg]    92
+0236228HF[P/min]   71
+0096228
\ No newline at end of file