diff --git a/ansiblelater/examples/standards.py b/ansiblelater/examples/standards.py
index 711466d..bfca01e 100644
--- a/ansiblelater/examples/standards.py
+++ b/ansiblelater/examples/standards.py
@@ -21,6 +21,7 @@ from ansiblelater.rules.ansiblefiles import check_shell_instead_command
 from ansiblelater.rules.ansiblefiles import check_command_has_changes
 from ansiblelater.rules.ansiblefiles import check_empty_string_compare
 from ansiblelater.rules.ansiblefiles import check_compare_to_literal_bool
+from ansiblelater.rules.ansiblefiles import check_uppercase_literal_bool
 
 
 tasks_should_be_separated = Standard(dict(
@@ -195,6 +196,14 @@ use_yaml_rather_than_key_value = Standard(dict(
     types=["playbook", "task", "handler"]
 ))
 
+literal_bool_should_start_with_uppercase = Standard(dict(
+    id="LINT0008",
+    name="Literal bools should start with a capital letter",
+    check=check_uppercase_literal_bool,
+    version="0.1",
+    types=["playbook", "task", "handler"]
+))
+
 
 ansible_min_version = '2.1'
 ansible_review_min_version = '0.1.0'
@@ -215,6 +224,7 @@ standards = [
     commands_should_be_idempotent,
     dont_compare_to_empty_string,
     dont_compare_to_literal_bool,
+    literal_bool_should_start_with_uppercase,
     # Lint
     files_should_not_contain_unnecessarily_empty_lines,
     files_should_be_indented,
diff --git a/ansiblelater/rules/ansiblefiles.py b/ansiblelater/rules/ansiblefiles.py
index ffd17cb..3f2d944 100644
--- a/ansiblelater/rules/ansiblefiles.py
+++ b/ansiblelater/rules/ansiblefiles.py
@@ -209,3 +209,19 @@ def check_delegate_to_localhost(candidate, settings):
                 errors.append(Error(task["__line__"], description))
 
     return Result(candidate.path, errors)
+
+
+def check_uppercase_literal_bool(candidate, settings):
+    yamllines, errors = get_normalized_yaml(candidate, settings)
+    description = "literal bools should be written as 'True|False' instead of 'true|false'"
+
+    lineno = 1
+    uppercase_bool = re.compile(r"([=!]=|:)\s*(true|false)")
+
+    if not errors:
+        for line in yamllines:
+            lineno += 1
+            if uppercase_bool.findall(line):
+                errors.append(Error(lineno, description))
+
+    return Result(candidate.path, errors)
diff --git a/ansiblelater/utils/yamlhelper.py b/ansiblelater/utils/yamlhelper.py
index c0ad6f3..1fbdcaf 100644
--- a/ansiblelater/utils/yamlhelper.py
+++ b/ansiblelater/utils/yamlhelper.py
@@ -486,23 +486,25 @@ def parse_yaml_linenumbers(data, filename):
 
 
 def normalized_yaml(file, options):
-    lines = []
+    # lines = []
     removes = []
 
     try:
         with codecs.open(file, mode='rb', encoding='utf-8') as f:
-            lines = f.readlines()
-            for line in lines:
-                if line.strip().startswith("#"):
-                    removes.append(line)
-                # remove document starter also
-                if options.get("remove_markers") and line.strip() == "---":
-                    removes.append(line)
-                # remove empty lines
-                if options.get("remove_empty") and not line.strip():
-                    removes.append(line)
-        for line in removes:
-            lines.remove(line)
+            lines = enumerate(f.readlines())
+        print(lines)
+        for i, line in lines:
+            if line.strip().startswith("#"):
+                removes.append(line)
+            # remove document starter also
+            if options.get("remove_markers") and line.strip() == "---":
+                removes.append(line)
+            # remove empty lines
+            if options.get("remove_empty") and not line.strip():
+                removes.append(line)
+
+        # for line in removes:
+        #     lines.remove(line)
     except (yaml.parser.ParserError, yaml.scanner.ScannerError) as e:
         raise LaterError("syntax error", e)
     return lines