diff --git a/src/interpreter/module.rs b/src/interpreter/module.rs
index 65bb1ee..7bdf4ca 100644
--- a/src/interpreter/module.rs
+++ b/src/interpreter/module.rs
@@ -305,7 +305,7 @@ fn prepare_function_locals(function_type: &FunctionType, function_body: &FuncBod
 		})
 		.collect::<Vec<_>>().into_iter().rev()
 		// TODO: default values (zero), not null
-		.chain(function_body.locals().iter().map(|l| VariableInstance::new(true, l.value_type().into(), RuntimeValue::Null)))
+		.chain(function_body.locals().iter().map(|l| VariableInstance::new(true, l.value_type().into(), RuntimeValue::default(l.value_type().into()))))
 		.collect::<Result<Vec<_>, _>>()
 }
 
diff --git a/src/interpreter/value.rs b/src/interpreter/value.rs
index c3dda58..e1de6c2 100644
--- a/src/interpreter/value.rs
+++ b/src/interpreter/value.rs
@@ -111,6 +111,17 @@ pub trait Float<T>: ArithmeticOps<T> {
 }
 
 impl RuntimeValue {
+	/// Creates new default value of given type.
+	pub fn default(variable_type: VariableType) -> Self {
+		match variable_type {
+			VariableType::AnyFunc => RuntimeValue::AnyFunc(0),
+			VariableType::I32 => RuntimeValue::I32(0),
+			VariableType::I64 => RuntimeValue::I64(0),
+			VariableType::F32 => RuntimeValue::F32(0f32),
+			VariableType::F64 => RuntimeValue::F64(0f64),
+		}
+	}
+
 	/// Creates new value by interpreting passed u32 as f32.
 	pub fn decode_f32(val: u32) -> Self {
 		RuntimeValue::F32(val.transmute_into())