diff --git a/libnfc/drivers/acr122.c b/libnfc/drivers/acr122.c
index 670dc50..dc6697b 100644
--- a/libnfc/drivers/acr122.c
+++ b/libnfc/drivers/acr122.c
@@ -166,7 +166,7 @@ acr122_list_devices(nfc_device_desc_t pnddDevices[], size_t szDevices, size_t *p
   while ((acDeviceNames[szPos] != '\0') && ((*pszDeviceFound) < szDevices)) {
     uiBusIndex++;
 
-    DBG("- %s (pos=%d)", acDeviceNames + szPos, szPos);
+    DBG("- %s (pos=%ld)", acDeviceNames + szPos, (unsigned long) szPos);
 
     bSupported = false;
     for (i = 0; supported_devices[i] && !bSupported; i++) {
diff --git a/libnfc/drivers/pn53x_usb.c b/libnfc/drivers/pn53x_usb.c
index 5ece91c..dd6fa84 100644
--- a/libnfc/drivers/pn53x_usb.c
+++ b/libnfc/drivers/pn53x_usb.c
@@ -141,14 +141,14 @@ bool pn53x_usb_list_devices(nfc_device_desc_t pnddDevices[], size_t szDevices, s
           // Test if we reach the maximum "wanted" devices
           if((*pszDeviceFound) == szDevices) 
           {
-            DBG("Found %d devices",*pszDeviceFound);
+            DBG("Found %ld devices", (unsigned long) *pszDeviceFound);
             return true;
           }
         }
       }
     }
   }
-  DBG("Found %d devices",*pszDeviceFound);
+  DBG("Found %ld devices", (unsigned long) *pszDeviceFound);
   if(*pszDeviceFound)
     return true;
   return false;
diff --git a/libnfc/nfc.c b/libnfc/nfc.c
index ed04105..ec351df 100644
--- a/libnfc/nfc.c
+++ b/libnfc/nfc.c
@@ -113,7 +113,7 @@ nfc_list_devices(nfc_device_desc_t pnddDevices[], size_t szDevices, size_t *pszD
       if (drivers_callbacks_list[uiDriver].list_devices (pnddDevices + (*pszDeviceFound), szDevices - (*pszDeviceFound), &szN))
       {
         *pszDeviceFound += szN;
-        DBG("%d device(s) found using %s driver", szN, drivers_callbacks_list[uiDriver].acDriver);
+        DBG("%ld device(s) found using %s driver", (unsigned long) szN, drivers_callbacks_list[uiDriver].acDriver);
       }
     }
     else
@@ -613,7 +613,7 @@ nfc_initiator_poll_targets(const nfc_device_t* pnd,
   res = pnd->pdc->transceive(pnd->nds, pbtTxInAutoPoll, szTxInAutoPoll, abtRx, &szRxLen);
 
   if((szRxLen == 0)||(res == false)) {
-    DBG("pnd->pdc->tranceive() failed: szRxLen=%d, res=%d", szRxLen, res);
+    DBG("pnd->pdc->tranceive() failed: szRxLen=%ld, res=%d", (unsigned long) szRxLen, res);
     return false;
   } else {
     *pszTargetFound = abtRx[0];