diff --git a/py2wasm/python.py b/py2wasm/python.py
index 57d004e..77b53d2 100644
--- a/py2wasm/python.py
+++ b/py2wasm/python.py
@@ -373,10 +373,28 @@ class Visitor:
             assert isinstance(node.value, int)
             assert -2147483648 <= node.value <= 2147483647
 
-            yield wasm.Statement(
-                '{}.const'.format(exp_type),
-                str(node.value)
-            )
+            yield wasm.Statement('i32.const', str(node.value))
+            return
+
+        if 'i64' == exp_type:
+            assert isinstance(node.value, int)
+            assert -9223372036854775808 <= node.value <= 9223372036854775807
+
+            yield wasm.Statement('i64.const', str(node.value))
+            return
+
+        if 'f32' == exp_type:
+            assert isinstance(node.value, float)
+            # TODO: Size check?
+
+            yield wasm.Statement('f32.const', node.value.hex())
+            return
+
+        if 'f64' == exp_type:
+            assert isinstance(node.value, float)
+            # TODO: Size check?
+
+            yield wasm.Statement('f64.const', node.value.hex())
             return
 
         raise NotImplementedError(exp_type)
@@ -386,6 +404,17 @@ class Visitor:
         Visits a Name node as (part of) an expression
         """
         assert node.id in wlocals
+
+        if exp_type == 'i64' and wlocals[node.id] == 'i32':
+            yield wasm.Statement('local.get', '${}'.format(node.id))
+            yield wasm.Statement('i64.extend_i32_s')
+            return
+
+        if exp_type == 'f64' and wlocals[node.id] == 'f32':
+            yield wasm.Statement('local.get', '${}'.format(node.id))
+            yield wasm.Statement('f64.promote_f32')
+            return
+
         assert exp_type == wlocals[node.id]
         yield wasm.Statement(
             'local.get',
@@ -442,5 +471,5 @@ def _parse_annotation(ann: Optional[ast.expr]) -> str:
     assert ann is not None, 'Web Assembly requires type annotations'
     assert isinstance(ann, ast.Name)
     result = ann.id
-    assert result in ['i32']
+    assert result in ['i32', 'i64', 'f32', 'f64']
     return result
diff --git a/tests/integration/test_simple.py b/tests/integration/test_simple.py
index af73c4d..7650c6c 100644
--- a/tests/integration/test_simple.py
+++ b/tests/integration/test_simple.py
@@ -3,7 +3,7 @@ import pytest
 from .helpers import Suite
 
 @pytest.mark.integration_test
-def test_return():
+def test_return_i32():
     code_py = """
 @exported
 def testEntry() -> i32:
@@ -15,6 +15,45 @@ def testEntry() -> i32:
     assert 13 == result.returned_value
     assert [] == result.log_int32_list
 
+@pytest.mark.integration_test
+def test_return_i64():
+    code_py = """
+@exported
+def testEntry() -> i64:
+    return 13
+"""
+
+    result = Suite(code_py, 'test_return').run_code()
+
+    assert 13 == result.returned_value
+    assert [] == result.log_int32_list
+
+@pytest.mark.integration_test
+def test_return_f32():
+    code_py = """
+@exported
+def testEntry() -> f32:
+    return 13.5
+"""
+
+    result = Suite(code_py, 'test_return').run_code()
+
+    assert 13.5 == result.returned_value
+    assert [] == result.log_int32_list
+
+@pytest.mark.integration_test
+def test_return_f64():
+    code_py = """
+@exported
+def testEntry() -> f64:
+    return 13.5
+"""
+
+    result = Suite(code_py, 'test_return').run_code()
+
+    assert 13.5 == result.returned_value
+    assert [] == result.log_int32_list
+
 @pytest.mark.integration_test
 def test_arg():
     code_py = """
@@ -28,6 +67,58 @@ def testEntry(a: i32) -> i32:
     assert 125 == result.returned_value
     assert [] == result.log_int32_list
 
+@pytest.mark.integration_test
+def test_i32_to_i64():
+    code_py = """
+@exported
+def testEntry(a: i32) -> i64:
+    return a
+"""
+
+    result = Suite(code_py, 'test_return').run_code(125)
+
+    assert 125 == result.returned_value
+    assert [] == result.log_int32_list
+
+@pytest.mark.integration_test
+def test_i32_plus_i64():
+    code_py = """
+@exported
+def testEntry(a: i32, b: i64) -> i64:
+    return a + b
+"""
+
+    result = Suite(code_py, 'test_return').run_code(125, 100)
+
+    assert 225 == result.returned_value
+    assert [] == result.log_int32_list
+
+@pytest.mark.integration_test
+def test_f32_to_f64():
+    code_py = """
+@exported
+def testEntry(a: f32) -> f64:
+    return a
+"""
+
+    result = Suite(code_py, 'test_return').run_code(125.5)
+
+    assert 125.5 == result.returned_value
+    assert [] == result.log_int32_list
+
+@pytest.mark.integration_test
+def test_f32_plus_f64():
+    code_py = """
+@exported
+def testEntry(a: f32, b: f64) -> f64:
+    return a + b
+"""
+
+    result = Suite(code_py, 'test_return').run_code(125.5, 100.25)
+
+    assert 225.75 == result.returned_value
+    assert [] == result.log_int32_list
+
 @pytest.mark.integration_test
 def test_uadd():
     code_py = """