diff --git a/include/plasp/utils/IO.h b/include/plasp/utils/IO.h
index f16ddd5..d2d022e 100644
--- a/include/plasp/utils/IO.h
+++ b/include/plasp/utils/IO.h
@@ -40,18 +40,6 @@ inline std::string unescapeASP(const std::string &string)
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-inline std::string toLowerCase(const std::string &string)
-{
-	std::string result;
-	result.resize(string.size());
-
-	std::transform(string.begin(), string.end(), result.begin(), ::tolower);
-
-	return result;
-}
-
-////////////////////////////////////////////////////////////////////////////////////////////////////
-
 }
 }
 
diff --git a/include/plasp/utils/Parser.h b/include/plasp/utils/Parser.h
index d41917c..5b1b118 100644
--- a/include/plasp/utils/Parser.h
+++ b/include/plasp/utils/Parser.h
@@ -24,6 +24,8 @@ class Parser
 		size_t row() const;
 		size_t column() const;
 
+		void setCaseSensitive(bool isCaseInsensitive = true);
+
 		char currentCharacter() const;
 		void advance();
 		bool advanceIf(char expectedCharacter);
@@ -63,6 +65,8 @@ class Parser
 		size_t m_row;
 		size_t m_column;
 
+		bool m_isCaseSensitive;
+
 		bool m_endOfFile;
 };
 
diff --git a/src/plasp/pddl/Action.cpp b/src/plasp/pddl/Action.cpp
index 2c11502..1124901 100644
--- a/src/plasp/pddl/Action.cpp
+++ b/src/plasp/pddl/Action.cpp
@@ -51,7 +51,7 @@ Action &Action::parseDeclaration(Context &context)
 	{
 		context.parser.expect<std::string>(":");
 
-		const auto sectionIdentifier = utils::toLowerCase(context.parser.parseIdentifier(isIdentifier));
+		const auto sectionIdentifier = context.parser.parseIdentifier(isIdentifier);
 
 		if (sectionIdentifier == "precondition")
 			action->m_precondition = parsePreconditionExpression(context, action->m_parameters);
diff --git a/src/plasp/pddl/Description.cpp b/src/plasp/pddl/Description.cpp
index 3eb8598..e7b34a4 100644
--- a/src/plasp/pddl/Description.cpp
+++ b/src/plasp/pddl/Description.cpp
@@ -22,6 +22,7 @@ Description::Description(std::istream &istream)
 :	m_parser(istream),
 	m_context(m_parser)
 {
+	m_parser.setCaseSensitive(false);
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
diff --git a/src/plasp/pddl/Domain.cpp b/src/plasp/pddl/Domain.cpp
index 5a5a527..334fc7c 100644
--- a/src/plasp/pddl/Domain.cpp
+++ b/src/plasp/pddl/Domain.cpp
@@ -105,7 +105,7 @@ void Domain::parseSection()
 	m_context.parser.expect<std::string>("(");
 	m_context.parser.expect<std::string>(":");
 
-	const auto sectionIdentifier = utils::toLowerCase(m_context.parser.parseIdentifier(isIdentifier));
+	const auto sectionIdentifier = m_context.parser.parseIdentifier(isIdentifier);
 
 	const auto skipSection =
 		[&]()
diff --git a/src/plasp/pddl/Expression.cpp b/src/plasp/pddl/Expression.cpp
index 09f6e43..04baf11 100644
--- a/src/plasp/pddl/Expression.cpp
+++ b/src/plasp/pddl/Expression.cpp
@@ -43,7 +43,7 @@ ExpressionPointer parsePreconditionExpression(Context &context,
 {
 	context.parser.expect<std::string>("(");
 
-	const auto expressionIdentifier = utils::toLowerCase(context.parser.parseIdentifier(isIdentifier));
+	const auto expressionIdentifier = context.parser.parseIdentifier(isIdentifier);
 
 	ExpressionPointer expression;
 
@@ -71,7 +71,7 @@ ExpressionPointer parseExpression(Context &context, const expressions::Variables
 {
 	context.parser.expect<std::string>("(");
 
-	const auto expressionIdentifier = utils::toLowerCase(context.parser.parseIdentifier(isIdentifier));
+	const auto expressionIdentifier = context.parser.parseIdentifier(isIdentifier);
 
 	auto expression = parseExpressionContent(expressionIdentifier, context, parameters);
 
@@ -136,7 +136,7 @@ ExpressionPointer parseEffectExpression(Context &context, const expressions::Var
 {
 	context.parser.expect<std::string>("(");
 
-	const auto expressionIdentifier = utils::toLowerCase(context.parser.parseIdentifier(isIdentifier));
+	const auto expressionIdentifier = context.parser.parseIdentifier(isIdentifier);
 
 	ExpressionPointer expression;
 
diff --git a/src/plasp/pddl/Problem.cpp b/src/plasp/pddl/Problem.cpp
index 60dd461..62dedf2 100644
--- a/src/plasp/pddl/Problem.cpp
+++ b/src/plasp/pddl/Problem.cpp
@@ -71,7 +71,7 @@ void Problem::parseSection()
 	m_context.parser.expect<std::string>("(");
 	m_context.parser.expect<std::string>(":");
 
-	const auto sectionIdentifier = utils::toLowerCase(m_context.parser.parseIdentifier(isIdentifier));
+	const auto sectionIdentifier = m_context.parser.parseIdentifier(isIdentifier);
 
 	const auto skipSection =
 		[&]()
diff --git a/src/plasp/pddl/Requirement.cpp b/src/plasp/pddl/Requirement.cpp
index 834fc86..451ee0f 100644
--- a/src/plasp/pddl/Requirement.cpp
+++ b/src/plasp/pddl/Requirement.cpp
@@ -82,7 +82,7 @@ Requirement::Requirement(Requirement::Type type)
 
 Requirement Requirement::parse(Context &context)
 {
-	const auto requirementName = utils::toLowerCase(context.parser.parseIdentifier(isIdentifier));
+	const auto requirementName = context.parser.parseIdentifier(isIdentifier);
 
 	const auto match = requirementTypesToPDDL.right.find(requirementName);
 
diff --git a/src/plasp/utils/Parser.cpp b/src/plasp/utils/Parser.cpp
index e350b74..dddaec4 100644
--- a/src/plasp/utils/Parser.cpp
+++ b/src/plasp/utils/Parser.cpp
@@ -26,6 +26,7 @@ Parser::Parser(std::istream &istream)
 	m_position(m_istream),
 	m_row{1},
 	m_column{1},
+	m_isCaseSensitive{true},
 	m_endOfFile{false}
 {
 	std::setlocale(LC_NUMERIC, "C");
@@ -52,11 +53,21 @@ size_t Parser::column() const
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
+void Parser::setCaseSensitive(bool isCaseSensitive)
+{
+	m_isCaseSensitive = isCaseSensitive;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
 char Parser::currentCharacter() const
 {
 	checkStream();
 
-	return *m_position;
+	if (m_isCaseSensitive)
+		return *m_position;
+
+	return std::tolower(*m_position);
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
diff --git a/tests/TestPDDLParser.cpp b/tests/TestPDDLParser.cpp
index 78a75dd..0bbff48 100644
--- a/tests/TestPDDLParser.cpp
+++ b/tests/TestPDDLParser.cpp
@@ -58,7 +58,7 @@ TEST_F(PDDLParserTests, ParseBlocksWorldDomain)
 		const auto &domain = description.domain();
 
 		// Name
-		ASSERT_EQ(domain.name(), "BLOCKS");
+		ASSERT_EQ(domain.name(), "blocks");
 
 		// Requirements
 		ASSERT_EQ(domain.requirements().size(), 2u);
@@ -113,7 +113,7 @@ TEST_F(PDDLParserTests, ParseStorageDomain)
 		const auto &domain = description.domain();
 
 		// Name
-		ASSERT_EQ(domain.name(), "Storage-Propositional");
+		ASSERT_EQ(domain.name(), "storage-propositional");
 
 		// Requirements
 		ASSERT_EQ(domain.requirements().size(), 1u);