Nowadays we use vehicle registration plate numbers increasingly frequently, e.g. for parking in paid parking zones or when using recordings from private on-board cameras. The processing of registration numbers can have a significant impact on the rights and freedoms of every citizen; therefore, it is essential to unambiguously determine whether vehicle registration plate numbers ought to be classified as personal data. This issue is varyingly interpreted by the case law of Polish courts and by the President of the Office for Personal Data Protection. This debate boils down to the question of whether we are able to identify a given individual based solely on a vehicle registration plate number. Administrative courts, as a rule, state that registration plates do not constitute personal data due to the fact that registration numbers identify a vehicle, not an individual. However, the President of the Office for Personal Data Protection is of a contrasting opinion, believing that indirect identification allows us to determine the owner of a vehicle based solely on the registration plate number.