Real-world emissions measurements of 31 diesel and 48 gasoline Euro 6 vehicles were conducted using a Portable Emissions Measurement System (PEMS) in the region of Stuttgart, Germany. The SEMTECH CPN device was used to record Particle Number (PN) concentrations during the tests. The real-driving emission factors of PN concentrations were obtained on various road types. Both diesel and gasoline engines PN emissions exhibited a significant correlation with the change in vehicle speed and power demand. Except for two vehicles, the European regulations are largely met by most of the vehicles. The impact of the regeneration events on emissions was also studied.