A method for providing safe access of a mobile control unit (1) to a field device (2), wherein, in particular, the field device is protected against unauthorized access via a mobile control unit is achieved in that a connection for transmitting data is established between the mobile control unit (1) and the field device (2), that access data for access is exchanged, that a comparison is made between the access data and stored comparison data and a comparison result is generated, and that access of the mobile control unit (1) to the field device (1) is permitted based on the comparison result.