diff --git a/docs/test_cases.md b/docs/test_cases.md
index 9f87eca0..e4da3ba2 100644
--- a/docs/test_cases.md
+++ b/docs/test_cases.md
@@ -24,6 +24,7 @@
  * [t00023](./test_cases/t00023.md) - Strategy pattern
  * [t00024](./test_cases/t00024.md) - Proxy pattern
  * [t00025](./test_cases/t00025.md) - Template proxy pattern
+ * [t00026](./test_cases/t00026.md) - Template memento pattern
 ## Sequence diagrams
  * [t20001](./test_cases/t20001.md) - Basic sequence diagram
 ## Configuration diagrams
diff --git a/docs/test_cases/t00026.md b/docs/test_cases/t00026.md
new file mode 100644
index 00000000..fece16cc
--- /dev/null
+++ b/docs/test_cases/t00026.md
@@ -0,0 +1,83 @@
+# t00026 - Template memento pattern
+## Config
+```yaml
+compilation_database_dir: ..
+output_directory: puml
+diagrams:
+  t00026_class:
+    type: class
+    glob:
+      - ../../tests/t00026/t00026.cc
+    using_namespace:
+      - clanguml::t00026
+    include:
+      namespaces:
+        - clanguml::t00026
+
+```
+## Source code
+File t00026.cc
+```cpp
+#include <iostream>
+#include <memory>
+#include <unordered_map>
+
+namespace clanguml {
+namespace t00026 {
+
+template <typename T> class Memento {
+public:
+    Memento(T &&v)
+        : m_value(std::forward<T>(v))
+    {
+    }
+
+    T value() const { return m_value; }
+
+private:
+    T m_value;
+};
+
+template <typename T> class Originator {
+public:
+    Originator(T &&v)
+        : m_value(std::forward<T>(v))
+    {
+    }
+
+    Memento<T> memoize_value() const { return Memento<T>{m_value}; }
+
+    void load(const Memento<T> &m) { m_value = m.value(); }
+
+    void print() const { std::cout << m_value << std::endl; }
+
+    void set(T &&v) { m_value = std::forward<T>(v); }
+
+private:
+    T m_value;
+};
+
+template <typename T> class Caretaker {
+public:
+    Memento<T> &state(const std::string &n) { return m_mementos.at(n); }
+
+    void set_state(const std::string &s, Memento<T> &&m)
+    {
+        m_mementos.try_emplace(s, std::move(m));
+    }
+
+private:
+    std::unordered_map<std::string, Memento<T>> m_mementos;
+};
+
+struct StringMemento {
+    Caretaker<std::string> caretaker;
+    Originator<std::string> originator;
+};
+
+}
+}
+
+```
+## Generated UML diagrams
+![t00026_class](./t00026_class.png "Template memento pattern")
diff --git a/docs/test_cases/t00026_class.png b/docs/test_cases/t00026_class.png
new file mode 100644
index 00000000..45dc0e97
Binary files /dev/null and b/docs/test_cases/t00026_class.png differ
diff --git a/tests/t00026/.clanguml b/tests/t00026/.clanguml
new file mode 100644
index 00000000..33224cee
--- /dev/null
+++ b/tests/t00026/.clanguml
@@ -0,0 +1,12 @@
+compilation_database_dir: ..
+output_directory: puml
+diagrams:
+  t00026_class:
+    type: class
+    glob:
+      - ../../tests/t00026/t00026.cc
+    using_namespace:
+      - clanguml::t00026
+    include:
+      namespaces:
+        - clanguml::t00026
diff --git a/tests/t00026/t00026.cc b/tests/t00026/t00026.cc
new file mode 100644
index 00000000..747e8f4b
--- /dev/null
+++ b/tests/t00026/t00026.cc
@@ -0,0 +1,58 @@
+#include <iostream>
+#include <memory>
+#include <unordered_map>
+
+namespace clanguml {
+namespace t00026 {
+
+template <typename T> class Memento {
+public:
+    Memento(T &&v)
+        : m_value(std::forward<T>(v))
+    {
+    }
+
+    T value() const { return m_value; }
+
+private:
+    T m_value;
+};
+
+template <typename T> class Originator {
+public:
+    Originator(T &&v)
+        : m_value(std::forward<T>(v))
+    {
+    }
+
+    Memento<T> memoize_value() const { return Memento<T>{m_value}; }
+
+    void load(const Memento<T> &m) { m_value = m.value(); }
+
+    void print() const { std::cout << m_value << std::endl; }
+
+    void set(T &&v) { m_value = std::forward<T>(v); }
+
+private:
+    T m_value;
+};
+
+template <typename T> class Caretaker {
+public:
+    Memento<T> &state(const std::string &n) { return m_mementos.at(n); }
+
+    void set_state(const std::string &s, Memento<T> &&m)
+    {
+        m_mementos.try_emplace(s, std::move(m));
+    }
+
+private:
+    std::unordered_map<std::string, Memento<T>> m_mementos;
+};
+
+struct StringMemento {
+    Caretaker<std::string> caretaker;
+    Originator<std::string> originator;
+};
+}
+}
diff --git a/tests/t00026/test_case.h b/tests/t00026/test_case.h
new file mode 100644
index 00000000..4dc8892c
--- /dev/null
+++ b/tests/t00026/test_case.h
@@ -0,0 +1,54 @@
+/**
+ * tests/t00026/test_case.cc
+ *
+ * Copyright (c) 2021 Bartek Kryza <bkryza@gmail.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+TEST_CASE("t00026", "[test-case][class]")
+{
+    auto [config, db] = load_config("t00026");
+
+    auto diagram = config.diagrams["t00026_class"];
+
+    REQUIRE(diagram->name == "t00026_class");
+
+    REQUIRE(diagram->include.namespaces.size() == 1);
+    REQUIRE_THAT(diagram->include.namespaces,
+        VectorContains(std::string{"clanguml::t00026"}));
+
+    REQUIRE(diagram->exclude.namespaces.size() == 0);
+
+    REQUIRE(diagram->should_include("clanguml::t00026::A"));
+
+    auto model = generate_class_diagram(db, diagram);
+
+    REQUIRE(model.name == "t00026_class");
+
+    auto puml = generate_class_puml(diagram, model);
+    AliasMatcher _A(puml);
+
+    REQUIRE_THAT(puml, StartsWith("@startuml"));
+    REQUIRE_THAT(puml, EndsWith("@enduml\n"));
+    REQUIRE_THAT(puml, IsClassTemplate("Memento", "T"));
+    REQUIRE_THAT(puml, IsClassTemplate("Originator", "T"));
+    REQUIRE_THAT(puml, IsClassTemplate("Caretaker", "T"));
+    REQUIRE_THAT(puml,
+        IsInstantiation(_A("Originator<T>"), _A("Originator<std::string>")));
+    REQUIRE_THAT(puml,
+        IsInstantiation(_A("Caretaker<T>"), _A("Caretaker<std::string>")));
+
+    save_puml(
+        "./" + config.output_directory + "/" + diagram->name + ".puml", puml);
+}
diff --git a/tests/test_cases.cc b/tests/test_cases.cc
index 36c830a8..c2140124 100644
--- a/tests/test_cases.cc
+++ b/tests/test_cases.cc
@@ -129,6 +129,7 @@ using namespace clanguml::test::matchers;
 #include "t00023/test_case.h"
 #include "t00024/test_case.h"
 #include "t00025/test_case.h"
+#include "t00026/test_case.h"
 
 //
 // Sequence diagram tests
diff --git a/tests/test_cases.yaml b/tests/test_cases.yaml
index ab33058f..72ab5a2f 100644
--- a/tests/test_cases.yaml
+++ b/tests/test_cases.yaml
@@ -72,6 +72,9 @@ test_cases:
     - name: t00025
       title: Template proxy pattern
       description:
+    - name: t00026
+      title: Template memento pattern
+      description:
   Sequence diagrams:
     - name: t20001
       title: Basic sequence diagram