diff --git a/lib/pddl/tests/TestNormalization.cpp b/lib/pddl/tests/TestNormalization.cpp
index 457d433..0bd989f 100644
--- a/lib/pddl/tests/TestNormalization.cpp
+++ b/lib/pddl/tests/TestNormalization.cpp
@@ -429,3 +429,67 @@ TEST_CASE("[normalization] Nested expressions are correctly flattened via derive
 		CHECK(a31212->arguments[1].get<pddl::normalizedAST::VariablePointer>()->declaration == a312->declaration->existentialParameters[0].get());
 	}
 }
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+TEST_CASE("[normalization] Derived predicates are correctly numbered", "[normalization]")
+{
+	pddl::Tokenizer tokenizer;
+	pddl::Context context(std::move(tokenizer), ignoreWarnings);
+
+	SECTION("derived predicates introduced by both domain and problem")
+	{
+		const auto domainFile = fs::path("data") / "normalization" / "normalization-6-1.pddl";
+		context.tokenizer.read(domainFile);
+		auto description = pddl::parseDescription(context);
+		const auto normalizedDescription = pddl::normalize(std::move(description));
+
+		const auto &domain = normalizedDescription.domain;
+		const auto &problem = normalizedDescription.problem.value();
+
+		REQUIRE(domain->derivedPredicates.size() == 4);
+		REQUIRE(problem->derivedPredicates.size() == 2);
+
+		CHECK(domain->derivedPredicates[0]->name == "derived-predicate-1");
+		CHECK(domain->derivedPredicates[1]->name == "derived-predicate-2");
+		CHECK(domain->derivedPredicates[2]->name == "derived-predicate-3");
+		CHECK(domain->derivedPredicates[3]->name == "derived-predicate-4");
+		CHECK(problem->derivedPredicates[0]->name == "derived-predicate-5");
+		CHECK(problem->derivedPredicates[1]->name == "derived-predicate-6");
+	}
+
+	SECTION("derived predicates introduced by domain only")
+	{
+		const auto domainFile = fs::path("data") / "normalization" / "normalization-6-2.pddl";
+		context.tokenizer.read(domainFile);
+		auto description = pddl::parseDescription(context);
+		const auto normalizedDescription = pddl::normalize(std::move(description));
+
+		const auto &domain = normalizedDescription.domain;
+		REQUIRE(!normalizedDescription.problem);
+
+		REQUIRE(domain->derivedPredicates.size() == 4);
+
+		CHECK(domain->derivedPredicates[0]->name == "derived-predicate-1");
+		CHECK(domain->derivedPredicates[1]->name == "derived-predicate-2");
+		CHECK(domain->derivedPredicates[2]->name == "derived-predicate-3");
+		CHECK(domain->derivedPredicates[3]->name == "derived-predicate-4");
+	}
+
+	SECTION("derived predicates introduced by both domain and problem")
+	{
+		const auto domainFile = fs::path("data") / "normalization" / "normalization-6-3.pddl";
+		context.tokenizer.read(domainFile);
+		auto description = pddl::parseDescription(context);
+		const auto normalizedDescription = pddl::normalize(std::move(description));
+
+		const auto &domain = normalizedDescription.domain;
+		const auto &problem = normalizedDescription.problem.value();
+
+		REQUIRE(domain->derivedPredicates.empty());
+		REQUIRE(problem->derivedPredicates.size() == 2);
+
+		CHECK(problem->derivedPredicates[0]->name == "derived-predicate-1");
+		CHECK(problem->derivedPredicates[1]->name == "derived-predicate-2");
+	}
+}
diff --git a/tests/data/normalization/normalization-6-1.pddl b/tests/data/normalization/normalization-6-1.pddl
new file mode 100644
index 0000000..85a9466
--- /dev/null
+++ b/tests/data/normalization/normalization-6-1.pddl
@@ -0,0 +1,47 @@
+; tests derived predicates are correclty numbered
+; variation 1: derived predicates both in domain and problem
+(define (domain test-normalization)
+	(:predicates
+		(test-predicate-0))
+
+	; introduces derived predicates 1 and 2
+	(:action test-action-1
+		:parameters
+			(?x)
+		:precondition
+			(or
+				(test-predicate-0)
+				(and
+					(test-predicate-0)
+					(test-predicate-0)))
+		:effect
+			(test-predicate-0))
+
+	; introduces derived predicates 3 and 4
+	(:action test-action-1
+		:parameters
+			(?x)
+		:precondition
+			(or
+				(test-predicate-0)
+				(and
+					(test-predicate-0)
+					(test-predicate-0)))
+		:effect
+			(test-predicate-0)))
+
+(define (problem test-normalization)
+	(:domain test-normalization)
+
+	(:objects a b c)
+
+	(:init
+		(test-predicate-0))
+
+	; introduces derived predicates 5 and 6
+	(:goal
+		(or
+			(test-predicate-0)
+			(and
+				(test-predicate-0)
+				(test-predicate-0)))))
diff --git a/tests/data/normalization/normalization-6-2.pddl b/tests/data/normalization/normalization-6-2.pddl
new file mode 100644
index 0000000..edb5162
--- /dev/null
+++ b/tests/data/normalization/normalization-6-2.pddl
@@ -0,0 +1,32 @@
+; tests derived predicates are correclty numbered
+; variation 2: derived predicates in domain only
+(define (domain test-normalization)
+	(:predicates
+		(test-predicate-0))
+
+	; introduces derived predicates 1 and 2
+	(:action test-action-1
+		:parameters
+			(?x)
+		:precondition
+			(or
+				(test-predicate-0)
+				(and
+					(test-predicate-0)
+					(test-predicate-0)))
+		:effect
+			(test-predicate-0))
+
+	; introduces derived predicates 3 and 4
+	(:action test-action-1
+		:parameters
+			(?x)
+		:precondition
+			(or
+				(test-predicate-0)
+				(and
+					(test-predicate-0)
+					(test-predicate-0)))
+		:effect
+			(test-predicate-0))
+)
diff --git a/tests/data/normalization/normalization-6-3.pddl b/tests/data/normalization/normalization-6-3.pddl
new file mode 100644
index 0000000..234b100
--- /dev/null
+++ b/tests/data/normalization/normalization-6-3.pddl
@@ -0,0 +1,29 @@
+; tests derived predicates are correclty numbered
+; variation 3: derived predicates in problem only
+(define (domain test-normalization)
+	(:predicates
+		(test-predicate-0))
+
+	(:action test-action-1
+		:parameters
+			(?x)
+		:precondition
+			(test-predicate-0)
+		:effect
+			(test-predicate-0)))
+
+(define (problem test-normalization)
+	(:domain test-normalization)
+
+	(:objects a b c)
+
+	(:init
+		(test-predicate-0))
+
+	; introduces derived predicates 1 and 2
+	(:goal
+		(or
+			(test-predicate-0)
+			(and
+				(test-predicate-0)
+				(test-predicate-0)))))