diff --git a/nac3core/src/codegen/builtin_fns.rs b/nac3core/src/codegen/builtin_fns.rs
index 7c203df..3f0c08d 100644
--- a/nac3core/src/codegen/builtin_fns.rs
+++ b/nac3core/src/codegen/builtin_fns.rs
@@ -857,30 +857,84 @@ pub fn call_abs<'ctx, G: CodeGenerator + ?Sized>(
 pub fn call_numpy_isnan<'ctx, G: CodeGenerator + ?Sized>(
     generator: &mut G,
     ctx: &mut CodeGenContext<'ctx, '_>,
-    x: (Type, FloatValue<'ctx>),
-) -> IntValue<'ctx> {
+    x: (Type, BasicValueEnum<'ctx>),
+) -> Result<BasicValueEnum<'ctx>, String> {
+    const FN_NAME: &str = "np_isnan";
+
+    let llvm_usize = generator.get_size_type(ctx.ctx);
+
     let (x_ty, x) = x;
 
-    if !ctx.unifier.unioned(x_ty, ctx.primitives.float) {
-        unsupported_type(ctx, "np_isnan", &[x_ty])
-    }
+    Ok(match x.get_type() {
+        BasicTypeEnum::FloatType(_) => {
+            debug_assert!(ctx.unifier.unioned(x_ty, ctx.primitives.float));
 
-    irrt::call_isnan(generator, ctx, x)
+            irrt::call_isnan(generator, ctx, x.into_float_value()).into()
+        }
+
+        BasicTypeEnum::PointerType(_) if x_ty.obj_id(&ctx.unifier).is_some_and(|id| id == PRIMITIVE_DEF_IDS.ndarray) => {
+            let (elem_ty, _) = unpack_ndarray_var_tys(&mut ctx.unifier, x_ty);
+
+            let ndarray = ndarray_elementwise_unaryop_impl(
+                generator,
+                ctx,
+                ctx.primitives.bool,
+                None,
+                NDArrayValue::from_ptr_val(x.into_pointer_value(), llvm_usize, None),
+                |generator, ctx, val| {
+                    let val = call_numpy_isnan(generator, ctx, (elem_ty, val))?;
+
+                    Ok(generator.bool_to_i8(ctx, val.into_int_value()).into())
+                },
+            )?;
+
+            ndarray.as_ptr_value().into()
+        }
+
+        _ => unsupported_type(ctx, FN_NAME, &[x_ty])
+    })
 }
 
 /// Invokes the `np_isinf` builtin function.
 pub fn call_numpy_isinf<'ctx, G: CodeGenerator + ?Sized>(
     generator: &mut G,
     ctx: &mut CodeGenContext<'ctx, '_>,
-    x: (Type, FloatValue<'ctx>),
-) -> IntValue<'ctx> {
+    x: (Type, BasicValueEnum<'ctx>),
+) -> Result<BasicValueEnum<'ctx>, String> {
+    const FN_NAME: &str = "np_isinf";
+
+    let llvm_usize = generator.get_size_type(ctx.ctx);
+
     let (x_ty, x) = x;
 
-    if !ctx.unifier.unioned(x_ty, ctx.primitives.float) {
-        unsupported_type(ctx, "np_isinf", &[x_ty])
-    }
+    Ok(match x.get_type() {
+        BasicTypeEnum::FloatType(_) => {
+            debug_assert!(ctx.unifier.unioned(x_ty, ctx.primitives.float));
 
-    irrt::call_isinf(generator, ctx, x)
+            irrt::call_isinf(generator, ctx, x.into_float_value()).into()
+        }
+
+        BasicTypeEnum::PointerType(_) if x_ty.obj_id(&ctx.unifier).is_some_and(|id| id == PRIMITIVE_DEF_IDS.ndarray) => {
+            let (elem_ty, _) = unpack_ndarray_var_tys(&mut ctx.unifier, x_ty);
+
+            let ndarray = ndarray_elementwise_unaryop_impl(
+                generator,
+                ctx,
+                ctx.primitives.bool,
+                None,
+                NDArrayValue::from_ptr_val(x.into_pointer_value(), llvm_usize, None),
+                |generator, ctx, val| {
+                    let val = call_numpy_isinf(generator, ctx, (elem_ty, val))?;
+
+                    Ok(generator.bool_to_i8(ctx, val.into_int_value()).into())
+                },
+            )?;
+
+            ndarray.as_ptr_value().into()
+        }
+
+        _ => unsupported_type(ctx, FN_NAME, &[x_ty])
+    })
 }
 
 /// Invokes the `np_sin` builtin function.
diff --git a/nac3core/src/toplevel/builtins.rs b/nac3core/src/toplevel/builtins.rs
index f9049d9..cb5fb35 100644
--- a/nac3core/src/toplevel/builtins.rs
+++ b/nac3core/src/toplevel/builtins.rs
@@ -1393,10 +1393,9 @@ pub fn get_builtins(unifier: &mut Unifier, primitives: &PrimitiveStore) -> Built
             Box::new(|ctx, _, fun, args, generator| {
                 let x_ty = fun.0.args[0].ty;
                 let x_val = args[0].1.clone()
-                    .to_basic_value_enum(ctx, generator, x_ty)?
-                    .into_float_value();
+                    .to_basic_value_enum(ctx, generator, x_ty)?;
 
-                Ok(Some(builtin_fns::call_numpy_isnan(generator, ctx, (x_ty, x_val)).into()))
+                Ok(Some(builtin_fns::call_numpy_isnan(generator, ctx, (x_ty, x_val))?))
             }),
         ),
         create_fn_by_codegen(
@@ -1408,10 +1407,9 @@ pub fn get_builtins(unifier: &mut Unifier, primitives: &PrimitiveStore) -> Built
             Box::new(|ctx, _, fun, args, generator| {
                 let x_ty = fun.0.args[0].ty;
                 let x_val = args[0].1.clone()
-                    .to_basic_value_enum(ctx, generator, x_ty)?
-                    .into_float_value();
+                    .to_basic_value_enum(ctx, generator, x_ty)?;
 
-                Ok(Some(builtin_fns::call_numpy_isinf(generator, ctx, (x_ty, x_val)).into()))
+                Ok(Some(builtin_fns::call_numpy_isinf(generator, ctx, (x_ty, x_val))?))
             }),
         ),
         create_fn_by_codegen(
diff --git a/nac3core/src/typecheck/type_inferencer/mod.rs b/nac3core/src/typecheck/type_inferencer/mod.rs
index 7fa6c63..6ad97e7 100644
--- a/nac3core/src/typecheck/type_inferencer/mod.rs
+++ b/nac3core/src/typecheck/type_inferencer/mod.rs
@@ -855,12 +855,14 @@ impl<'a> Inferencer<'a> {
             "int32",
             "float",
             "bool",
+            "np_isnan",
+            "np_isinf",
         ].iter().any(|fun_id| id == &(*fun_id).into()) && args.len() == 1 {
             let target_ty = if id == &"int32".into() {
                 self.primitives.int32
             } else if id == &"float".into() {
                 self.primitives.float
-            } else if id == &"bool".into() {
+            } else if id == &"bool".into() || id == &"np_isnan".into() || id == &"np_isinf".into() {
                 self.primitives.bool
             } else { unreachable!() };
 
diff --git a/nac3standalone/demo/src/ndarray.py b/nac3standalone/demo/src/ndarray.py
index d803c80..fe080b9 100644
--- a/nac3standalone/demo/src/ndarray.py
+++ b/nac3standalone/demo/src/ndarray.py
@@ -1,3 +1,11 @@
+@extern
+def dbl_nan() -> float:
+    ...
+
+@extern
+def dbl_inf() -> float:
+    ...
+
 @extern
 def output_bool(x: bool):
     ...
@@ -758,6 +766,28 @@ def test_ndarray_abs():
     output_ndarray_float_2(x)
     output_ndarray_float_2(y)
 
+def test_ndarray_isnan():
+    x = np_identity(2)
+    x_isnan = np_isnan(x)
+    y = np_full([2, 2], dbl_nan())
+    y_isnan = np_isnan(y)
+
+    output_ndarray_float_2(x)
+    output_ndarray_bool_2(x_isnan)
+    output_ndarray_float_2(y)
+    output_ndarray_bool_2(y_isnan)
+
+def test_ndarray_isinf():
+    x = np_identity(2)
+    x_isinf = np_isinf(x)
+    y = np_full([2, 2], dbl_inf())
+    y_isinf = np_isinf(y)
+
+    output_ndarray_float_2(x)
+    output_ndarray_bool_2(x_isinf)
+    output_ndarray_float_2(y)
+    output_ndarray_bool_2(y_isinf)
+
 def run() -> int32:
     test_ndarray_ctor()
     test_ndarray_empty()
@@ -858,5 +888,7 @@ def run() -> int32:
     test_ndarray_round()
     test_ndarray_floor()
     test_ndarray_abs()
+    test_ndarray_isnan()
+    test_ndarray_isinf()
 
     return 0