diff --git a/include/plasp/pddl/Problem.h b/include/plasp/pddl/Problem.h
index 836554e..565c220 100644
--- a/include/plasp/pddl/Problem.h
+++ b/include/plasp/pddl/Problem.h
@@ -34,12 +34,16 @@ class Problem
 		bool hasRequirement(Requirement::Type requirementType) const;
 		void computeDerivedRequirements();
 
+		void parseObjectSection();
+
 		void checkConsistency();
 
 		Context &m_context;
 
 		std::string m_name;
 		Requirements m_requirements;
+
+		expressions::Constants m_objects;
 };
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
diff --git a/include/plasp/pddl/expressions/Constant.h b/include/plasp/pddl/expressions/Constant.h
index 939afca..eeebb2a 100644
--- a/include/plasp/pddl/expressions/Constant.h
+++ b/include/plasp/pddl/expressions/Constant.h
@@ -23,7 +23,7 @@ class Constant: public Expression
 {
 	public:
 		static ConstantPointer parseDeclaration(Context &context);
-		static void parseTypedDeclaration(Context &context);
+		static void parseTypedDeclaration(Context &context, Constants &constants);
 
 		static Constant *parseExisting(Context &context);
 
diff --git a/include/plasp/pddl/expressions/InitialState.h b/include/plasp/pddl/expressions/InitialState.h
new file mode 100644
index 0000000..ff94409
--- /dev/null
+++ b/include/plasp/pddl/expressions/InitialState.h
@@ -0,0 +1,27 @@
+#ifndef __PLASP__PDDL__EXPRESSIONS__INITIAL_STATE_H
+#define __PLASP__PDDL__EXPRESSIONS__INITIAL_STATE_H
+
+#include <plasp/pddl/Expression.h>
+
+namespace plasp
+{
+namespace pddl
+{
+namespace expressions
+{
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+//
+// Type
+//
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+ExpressionPointer parseInitialState(Context &context);
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+}
+}
+}
+
+#endif
diff --git a/src/plasp/pddl/Domain.cpp b/src/plasp/pddl/Domain.cpp
index 334fc7c..493689c 100644
--- a/src/plasp/pddl/Domain.cpp
+++ b/src/plasp/pddl/Domain.cpp
@@ -259,7 +259,7 @@ void Domain::parseConstantSection()
 	// Store constants
 	while (m_context.parser.currentCharacter() != ')')
 	{
-		expressions::Constant::parseTypedDeclaration(m_context);
+		expressions::Constant::parseTypedDeclaration(m_context, m_context.constants);
 
 		m_context.parser.skipWhiteSpace();
 	}
diff --git a/src/plasp/pddl/Problem.cpp b/src/plasp/pddl/Problem.cpp
index 62dedf2..75611ba 100644
--- a/src/plasp/pddl/Problem.cpp
+++ b/src/plasp/pddl/Problem.cpp
@@ -103,7 +103,7 @@ void Problem::parseSection()
 	else if (sectionIdentifier == "requirements")
 		parseRequirementSection();
 	else if (sectionIdentifier == "objects")
-		skipSection();
+		parseObjectSection();
 	else if (sectionIdentifier == "init")
 		skipSection();
 	else if (sectionIdentifier == "goal")
@@ -196,6 +196,23 @@ void Problem::computeDerivedRequirements()
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
+void Problem::parseObjectSection()
+{
+	m_context.parser.skipWhiteSpace();
+
+	// Store constants
+	while (m_context.parser.currentCharacter() != ')')
+	{
+		expressions::Constant::parseTypedDeclaration(m_context);
+
+		m_context.parser.skipWhiteSpace();
+	}
+
+	m_context.parser.expect<std::string>(")");
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
 void Problem::checkConsistency()
 {
 }
diff --git a/src/plasp/pddl/expressions/Constant.cpp b/src/plasp/pddl/expressions/Constant.cpp
index 6dfdee2..18af058 100644
--- a/src/plasp/pddl/expressions/Constant.cpp
+++ b/src/plasp/pddl/expressions/Constant.cpp
@@ -50,12 +50,12 @@ ConstantPointer Constant::parseDeclaration(Context &context)
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-void Constant::parseTypedDeclaration(Context &context)
+void Constant::parseTypedDeclaration(Context &context, Constants &constants)
 {
 	// Parse and store constant
-	context.constants.emplace_back(parseDeclaration(context));
+	constants.emplace_back(parseDeclaration(context));
 
-	const auto &constant = context.constants.back();
+	const auto &constant = constants.back();
 
 	// Flag constant as correctly declared in the types section
 	constant->setDeclared();
@@ -70,7 +70,7 @@ void Constant::parseTypedDeclaration(Context &context)
 	auto *type = PrimitiveType::parseExisting(context);
 
 	// Assign parent type to all types that were previously flagged
-	std::for_each(context.constants.begin(), context.constants.end(),
+	std::for_each(constants.begin(), constants.end(),
 		[&](auto &constant)
 		{
 			if (!constant->isDirty())
diff --git a/src/plasp/pddl/expressions/InitialState.cpp b/src/plasp/pddl/expressions/InitialState.cpp
new file mode 100644
index 0000000..4b4f449
--- /dev/null
+++ b/src/plasp/pddl/expressions/InitialState.cpp
@@ -0,0 +1,52 @@
+#include <plasp/pddl/expressions/Type.h>
+
+#include <plasp/pddl/Context.h>
+#include <plasp/pddl/expressions/Predicate.h>
+#include <plasp/utils/IO.h>
+
+namespace plasp
+{
+namespace pddl
+{
+namespace expressions
+{
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+//
+// InitialState
+//
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+void throwUnsupported(const utils::Parser &parser, const std::string &expressionIdentifier)
+{
+	throw utils::ParserException(parser, "Expression type \"" + expressionIdentifier + "\" currently unsupported in this context");
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+ExpressionPointer parseInitialState(Context &context)
+{
+	context.parser.expect<std::string>("(");
+
+	const auto expressionIdentifier = context.parser.parseIdentifier(isIdentifier);
+
+	ExpressionPointer expression;
+
+	if (expressionIdentifier == "at"
+		|| expressionIdentifier == "=")
+	{
+		throwUnsupported(context.parser, expressionIdentifier);
+	}
+
+	// TODO: implement predicate parsing
+
+	context.parser.expect<std::string>(")");
+
+	return expression;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+}
+}
+}