A microprocessor system intended for safety-critical control systems includes two synchronously operated central units (1, 2) which receive the same input data and process the same program, in addition, read-only memories (5, 10) and random-access memories (6, 11) for useful data and test data, and comparators (18, 19) which check the output signals of the central units (1, 2) and issue disconnecting signals in the event of non-correlation. The central units (1, 2) are connected to the memories and the input and output units by way of separate bus systems (3, 4) and coupled by driver stages (15, 16, 17) which enable the central units (1, 2) to jointly read and process the data available in the two bus systems (3, 4). A microprocessor system intended for safety-critical control systems includes two synchronously operated central units which receive the same input data and process the same program, in addition, read-only memories and random-access memories for useful data and test data, and comparators which check the output signals of the central units and issue disconnecting signals in the event of non-correlation. The central units are connected to the memories and the input and output units by way of separate bus systems and coupled by driver stages which enable the central units to jointly read and process the data available in the two bus systems.