diff --git a/fairmq/devices/FairMQSink.cxx b/fairmq/devices/FairMQSink.cxx
index 21e26371..5547220d 100644
--- a/fairmq/devices/FairMQSink.cxx
+++ b/fairmq/devices/FairMQSink.cxx
@@ -28,7 +28,7 @@ FairMQSink::FairMQSink()
 
 void FairMQSink::InitTask()
 {
-    fNumMsgs = fConfig->GetValue<int>("num-msgs");
+    fNumMsgs = fConfig->GetValue<uint64_t>("num-msgs");
     fInChannelName = fConfig->GetValue<string>("in-channel");
 }
 
diff --git a/fairmq/devices/FairMQSink.h b/fairmq/devices/FairMQSink.h
index 085dcfef..211357e7 100644
--- a/fairmq/devices/FairMQSink.h
+++ b/fairmq/devices/FairMQSink.h
@@ -26,7 +26,7 @@ class FairMQSink : public FairMQDevice
     virtual ~FairMQSink();
 
   protected:
-    int fNumMsgs;
+    uint64_t fNumMsgs;
     std::string fInChannelName;
 
     virtual void Run();
diff --git a/fairmq/run/runSink.cxx b/fairmq/run/runSink.cxx
index 0f481b63..f6acb27c 100644
--- a/fairmq/run/runSink.cxx
+++ b/fairmq/run/runSink.cxx
@@ -15,7 +15,7 @@ void addCustomOptions(bpo::options_description& options)
 {
     options.add_options()
         ("in-channel", bpo::value<std::string>()->default_value("data"), "Name of the input channel")
-        ("num-msgs", bpo::value<int>()->default_value(0), "Number of messages to receive");
+        ("num-msgs", bpo::value<uint64_t>()->default_value(0), "Number of messages to receive");
 }
 
 FairMQDevicePtr getDevice(const FairMQProgOptions& /*config*/)