diff --git a/headers/os/drivers/ACPI.h b/headers/os/drivers/ACPI.h
index 1706806e8e..2c25fb3fca 100644
--- a/headers/os/drivers/ACPI.h
+++ b/headers/os/drivers/ACPI.h
@@ -15,10 +15,15 @@ typedef struct acpi_object_type acpi_object_type;
 
 #define B_ACPI_MODULE_NAME "bus_managers/acpi/v1"
 
-/* This must be uint64 for 64 bit! */
+#ifdef B_HAIKU_64_BIT
+typedef uint64 acpi_physical_address;
+typedef uint64 acpi_io_address;
+typedef uint64 acpi_size;
+#else
 typedef uint32 acpi_physical_address;
 typedef uint32 acpi_io_address;
 typedef uint32 acpi_size;
+#endif
 
 /* Actually a ptr to a NS Node */
 typedef void *				acpi_handle;
diff --git a/src/add-ons/kernel/bus_managers/acpi/include/platform/achaiku.h b/src/add-ons/kernel/bus_managers/acpi/include/platform/achaiku.h
index f1c15d1882..82bbdc550d 100644
--- a/src/add-ons/kernel/bus_managers/acpi/include/platform/achaiku.h
+++ b/src/add-ons/kernel/bus_managers/acpi/include/platform/achaiku.h
@@ -144,8 +144,12 @@
 #define COMPILER_DEPENDENT_INT64	int64
 #define COMPILER_DEPENDENT_UINT64	uint64
 
-/* TODO: Add 64 bit when Haiku goes 64 bit */
+
+#ifdef B_HAIKU_64_BIT
+#define ACPI_MACHINE_WIDTH				64
+#else
 #define ACPI_MACHINE_WIDTH				32
+#endif
 
 
 #ifdef _KERNEL_MODE