diff --git a/src/NmeaParser/Nmea/Gga.cs b/src/NmeaParser/Nmea/Gga.cs
index b191bd9..c0d32f4 100644
--- a/src/NmeaParser/Nmea/Gga.cs
+++ b/src/NmeaParser/Nmea/Gga.cs
@@ -41,7 +41,8 @@ namespace NmeaParser.Messages
             Latitude = NmeaMessage.StringToLatitude(message[1], message[2]);
             Longitude = NmeaMessage.StringToLongitude(message[3], message[4]);
             Quality =  (Gga.FixQuality)int.Parse(message[5], CultureInfo.InvariantCulture);
-            NumberOfSatellites = int.Parse(message[6], CultureInfo.InvariantCulture);
+            if (!string.IsNullOrEmpty(message[6]))
+                NumberOfSatellites = int.Parse(message[6], CultureInfo.InvariantCulture);
             Hdop = NmeaMessage.StringToDouble(message[7]);
             Altitude = NmeaMessage.StringToDouble(message[8]);
             AltitudeUnits = message[9];
diff --git a/src/UnitTests/NmeaParser.Tests/NmeaMessages.cs b/src/UnitTests/NmeaParser.Tests/NmeaMessages.cs
index 7119721..5c60c32 100644
--- a/src/UnitTests/NmeaParser.Tests/NmeaMessages.cs
+++ b/src/UnitTests/NmeaParser.Tests/NmeaMessages.cs
@@ -251,6 +251,16 @@ namespace NmeaParser.Tests
             Assert.AreEqual(TimeSpan.FromSeconds(1), gga.TimeSinceLastDgpsUpdate);
         }
 
+        [TestMethod]
+        public void TestGPGGA_NoSats()
+        {
+            string input = "$GPGGA,181651.98,3403.47163804,N,11711.80926595,W,0,,,,M,,M,,*6E";
+            var msg = NmeaMessage.Parse(input);
+            Assert.IsInstanceOfType(msg, typeof(Gga));
+            Gga gga = (Gga)msg;
+            Assert.AreEqual(0, gga.NumberOfSatellites);
+        }
+
         [TestMethod]
         public void TestPtlna()
         {