An integrated microprocessor system for safety-critical control systems, comprising at least two microprocessor system modules each comprising at least one processor core, a read/write memory and a memory protection unit, and a read-only memory which is jointly assigned to the processor cores of the microprocessor system modules. Each of the microprocessor system modules executes a main program and a monitoring program which may comprise a plurality of subprograms. If the memory protection unit detects unauthorized operations by one of the programs for accessing a separate address area (A, B) of another program, then the respective memory protection unit assigns a separate address area (A, B) of the read/write memory to the main program and to the monitoring program.