diff --git a/nac3core/src/toplevel/builtins.rs b/nac3core/src/toplevel/builtins.rs
index 6552cf8..d734045 100644
--- a/nac3core/src/toplevel/builtins.rs
+++ b/nac3core/src/toplevel/builtins.rs
@@ -18,6 +18,7 @@ use crate::{
     codegen::{
         builtin_fns,
         classes::{ProxyValue, RangeValue},
+        model::*,
         numpy::*,
         object::{any::AnyObject, ndarray::NDArrayObject},
         stmt::exn_constructor,
@@ -513,7 +514,7 @@ 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)
             }
 
@@ -1392,7 +1393,10 @@ 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 in_ndarray_ty = self.unifier.get_fresh_var_with_range(
             &[self.primitives.ndarray],
@@ -1401,6 +1405,27 @@ impl<'a> BuiltinBuilder<'a> {
         );
 
         match prim {
+            PrimDef::FunNpSize => create_fn_by_codegen(
+                self.unifier,
+                &into_var_map([in_ndarray_ty]),
+                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_or_bit_cast(generator, ctx, Int32);
+                    Ok(Some(size.value.as_basic_value_enum()))
+                }),
+            ),
             PrimDef::FunNpShape | PrimDef::FunNpStrides => {
                 // The function signatures of `np_shape` an `np_size` are the same.
                 // Mixed together for convenience.
diff --git a/nac3core/src/toplevel/helper.rs b/nac3core/src/toplevel/helper.rs
index 1854afc..5096046 100644
--- a/nac3core/src/toplevel/helper.rs
+++ b/nac3core/src/toplevel/helper.rs
@@ -57,6 +57,7 @@ pub enum PrimDef {
     FunNpIdentity,
 
     // NumPy ndarray property getters
+    FunNpSize,
     FunNpShape,
     FunNpStrides,
 
@@ -247,6 +248,7 @@ 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 5bcf4bb..ca17c3d 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