diff --git a/nac3core/src/toplevel/builtins.rs b/nac3core/src/toplevel/builtins.rs
index c271ef9c..97c81e48 100644
--- a/nac3core/src/toplevel/builtins.rs
+++ b/nac3core/src/toplevel/builtins.rs
@@ -15,6 +15,7 @@ use crate::{
     codegen::{
         builtin_fns,
         classes::{ProxyValue, RangeValue},
+        model::*,
         numpy::*,
         object::{any::AnyObject, ndarray::NDArrayObject},
         stmt::exn_constructor,
@@ -512,7 +513,7 @@ impl<'a> BuiltinBuilder<'a> {
             | PrimDef::FunNpEye
             | PrimDef::FunNpIdentity => self.build_ndarray_other_factory_function(prim),
 
-            PrimDef::FunNpShape | PrimDef::FunNpStrides => {
+            PrimDef::FunNpSize | PrimDef::FunNpShape | PrimDef::FunNpStrides => {
                 self.build_ndarray_property_getter_function(prim)
             }
 
@@ -1391,7 +1392,10 @@ impl<'a> BuiltinBuilder<'a> {
     }
 
     fn build_ndarray_property_getter_function(&mut self, prim: PrimDef) -> TopLevelDef {
-        debug_assert_prim_is_allowed(prim, &[PrimDef::FunNpShape, PrimDef::FunNpStrides]);
+        debug_assert_prim_is_allowed(
+            prim,
+            &[PrimDef::FunNpSize, PrimDef::FunNpShape, PrimDef::FunNpStrides],
+        );
 
         let mut var_map = self.num_var_map.clone();
         var_map.insert(self.ndarray_dtype_tvar.id, self.ndarray_dtype_tvar.ty);
@@ -1403,6 +1407,26 @@ impl<'a> BuiltinBuilder<'a> {
         );
 
         match prim {
+            PrimDef::FunNpSize => create_fn_by_codegen(
+                self.unifier,
+                &VarMap::new(),
+                prim.name(),
+                self.primitives.int32,
+                &[(in_ndarray_ty.ty, "a")],
+                Box::new(|ctx, obj, fun, args, generator| {
+                    assert!(obj.is_none());
+                    assert_eq!(args.len(), 1);
+
+                    let ndarray_ty = fun.0.args[0].ty;
+                    let ndarray =
+                        args[0].1.clone().to_basic_value_enum(ctx, generator, ndarray_ty)?;
+                    let ndarray = AnyObject { ty: ndarray_ty, value: ndarray };
+                    let ndarray = NDArrayObject::from_object(generator, ctx, ndarray);
+
+                    let size = ndarray.size(generator, ctx).truncate(generator, ctx, Int32);
+                    Ok(Some(size.value.as_basic_value_enum()))
+                }),
+            ),
             PrimDef::FunNpShape | PrimDef::FunNpStrides => {
                 // The fnuction signatures of `np_shape` an `np_size` are the same.
 
diff --git a/nac3core/src/toplevel/helper.rs b/nac3core/src/toplevel/helper.rs
index c4225811..275b80d8 100644
--- a/nac3core/src/toplevel/helper.rs
+++ b/nac3core/src/toplevel/helper.rs
@@ -53,6 +53,7 @@ pub enum PrimDef {
     FunNpIdentity,
 
     // NumPy ndarray property getters
+    FunNpSize,
     FunNpShape,
     FunNpStrides,
 
@@ -243,6 +244,7 @@ impl PrimDef {
             PrimDef::FunNpIdentity => fun("np_identity", None),
 
             // NumPy NDArray property getters,
+            PrimDef::FunNpSize => fun("np_size", None),
             PrimDef::FunNpShape => fun("np_shape", None),
             PrimDef::FunNpStrides => fun("np_strides", None),
 
diff --git a/nac3standalone/demo/interpret_demo.py b/nac3standalone/demo/interpret_demo.py
index 5bcf4bb5..ca17c3da 100755
--- a/nac3standalone/demo/interpret_demo.py
+++ b/nac3standalone/demo/interpret_demo.py
@@ -180,6 +180,7 @@ def patch(module):
     module.np_array = np.array
 
     # NumPy NDArray property getters
+    module.np_size = np.size
     module.np_shape = np.shape
     module.np_strides = lambda ndarray: ndarray.strides