diff --git a/usb/iso.c b/usb/iso.c
index 7cd4dd0..05c1106 100644
--- a/usb/iso.c
+++ b/usb/iso.c
@@ -64,7 +64,26 @@ void print_xfer(struct libusb_transfer *xfer) {
 	}
 }
 
+// extract data from a non-isochronous transfer.
 int extract_data(struct libusb_transfer *xfer, void *raw, int max, unsigned char *status) {
+	int i;
+	unsigned char *in = xfer->buffer;
+	unsigned char *out = raw;
+
+    int len = xfer->actual_length;
+    if (len > max) {
+            len = max;
+    }
+    memcpy(out, in, len);
+   	if (xfer->status != 0 && *status == 0) {
+            *status = xfer->status;
+   	}
+    return len;
+}
+
+// extract data from an isochronous transfer. Very similar to extract_data, but
+// acquires data from xfer->iso_packet_desc array instead of xfer attributes.
+int extract_iso_data(struct libusb_transfer *xfer, void *raw, int max, unsigned char *status) {
 	int i;
 	int copied = 0;
 	unsigned char *in = xfer->buffer;
diff --git a/usb/transfer.go b/usb/transfer.go
index becfbf5..8e447d3 100644
--- a/usb/transfer.go
+++ b/usb/transfer.go
@@ -18,6 +18,7 @@ package usb
 #include <libusb-1.0/libusb.h>
 
 int extract_data(struct libusb_transfer *xfer, void *data, int max, unsigned char *status);
+int extract_iso_data(struct libusb_transfer *xfer, void *data, int max, unsigned char *status);
 int submit(struct libusb_transfer *xfer);
 */
 import "C"
@@ -50,7 +51,12 @@ func (t *usbTransfer) wait(b []byte) (n int, err error) {
 	case <-t.done:
 	}
 	var status uint8
-	n = int(C.extract_data(t.xfer, unsafe.Pointer(&b[0]), C.int(len(b)), (*C.uchar)(unsafe.Pointer(&status))))
+	switch TransferType(t.xfer._type) {
+	case TRANSFER_TYPE_ISOCHRONOUS:
+		n = int(C.extract_iso_data(t.xfer, unsafe.Pointer(&b[0]), C.int(len(b)), (*C.uchar)(unsafe.Pointer(&status))))
+	default:
+		n = int(C.extract_data(t.xfer, unsafe.Pointer(&b[0]), C.int(len(b)), (*C.uchar)(unsafe.Pointer(&status))))
+	}
 	if status != 0 {
 		err = TransferStatus(status)
 	}