diff --git a/src/abstract_tree/structure_definition.rs b/src/abstract_tree/structure_definition.rs
index a192c88..ab7090b 100644
--- a/src/abstract_tree/structure_definition.rs
+++ b/src/abstract_tree/structure_definition.rs
@@ -22,7 +22,9 @@ impl AbstractTree for StructureDefinition {
         Ok(Type::None)
     }
 
-    fn validate(&self, _context: &Context) -> Result<(), ValidationError> {
+    fn validate(&self, context: &Context) -> Result<(), ValidationError> {
+        context.set_type(self.name.clone(), Type::Named(self.name.clone()))?;
+
         Ok(())
     }
 
diff --git a/src/abstract_tree/value_node.rs b/src/abstract_tree/value_node.rs
index 2bb5d79..8567d9e 100644
--- a/src/abstract_tree/value_node.rs
+++ b/src/abstract_tree/value_node.rs
@@ -114,6 +114,14 @@ impl AbstractTree for ValueNode {
                 })?;
         }
 
+        if let ValueNode::Structure { name, fields } = self {
+            let r#type = if let Some(r#type) = context.get_type(name)? {
+                r#type
+            } else {
+                return Err(ValidationError::TypeNotFound(name.clone()));
+            };
+        }
+
         Ok(())
     }
 
diff --git a/tests/structs.rs b/tests/structs.rs
index 67a6c1f..db98905 100644
--- a/tests/structs.rs
+++ b/tests/structs.rs
@@ -1,4 +1,4 @@
-use dust_lang::{abstract_tree::Identifier, *};
+use dust_lang::{abstract_tree::Identifier, error::Error, *};
 
 #[test]
 fn simple_structure() {
@@ -57,3 +57,20 @@ fn nested_structure() {
         )))
     )
 }
+
+#[test]
+fn undefined_struct() {
+    assert_eq!(
+        interpret(
+            "
+                Foo {
+                    bar = 42
+                }
+            "
+        ),
+        Err(vec![Error::Validation {
+            error: error::ValidationError::TypeNotFound(Identifier::new("Foo")),
+            position: (17, 82).into()
+        }])
+    )
+}