diff --git a/headers/os/drivers/USB2.h b/headers/os/drivers/USB2.h
index 864c9270fb..2350fda09e 100644
--- a/headers/os/drivers/USB2.h
+++ b/headers/os/drivers/USB2.h
@@ -74,7 +74,7 @@ struct usb_configuration_info {
 };
 
 typedef void (*usb_callback_func)(void *cookie, uint32 status, void *data,
-	uint32 actualLength);
+	size_t actualLength);
 
 
 /* The usb_module_info represents the public API of the USB Stack. */
diff --git a/headers/os/drivers/USB3.h b/headers/os/drivers/USB3.h
index 1f36212880..43730119fb 100644
--- a/headers/os/drivers/USB3.h
+++ b/headers/os/drivers/USB3.h
@@ -80,7 +80,7 @@ typedef struct {
 } usb_iso_packet_descriptor;
 
 typedef void (*usb_callback_func)(void *cookie, uint32 status, void *data,
-	uint32 actualLength);
+	size_t actualLength);
 
 
 /* The usb_module_info represents the public API of the USB Stack. */
diff --git a/src/add-ons/kernel/bus_managers/usb/Hub.cpp b/src/add-ons/kernel/bus_managers/usb/Hub.cpp
index f70213c9dd..40881b9504 100644
--- a/src/add-ons/kernel/bus_managers/usb/Hub.cpp
+++ b/src/add-ons/kernel/bus_managers/usb/Hub.cpp
@@ -231,7 +231,7 @@ Hub::Explore()
 
 void
 Hub::InterruptCallback(void *cookie, uint32 status, void *data,
-	uint32 actualLength)
+	size_t actualLength)
 {
 	TRACE(("USB Hub: interrupt callback!\n"));
 }
diff --git a/src/add-ons/kernel/bus_managers/usb/usb_p.h b/src/add-ons/kernel/bus_managers/usb/usb_p.h
index 0625239b27..9a03de9624 100644
--- a/src/add-ons/kernel/bus_managers/usb/usb_p.h
+++ b/src/add-ons/kernel/bus_managers/usb/usb_p.h
@@ -426,7 +426,7 @@ virtual	status_t						GetDescriptor(uint8 descriptorType,
 		void							Explore();
 static	void							InterruptCallback(void *cookie,
 											uint32 status, void *data,
-											uint32 actualLength);
+											size_t actualLength);
 
 virtual	void							ReportDevice(
 											usb_support_descriptor *supportDescriptors,