The integrated circuits array with latch up protection includes an active array and a guard array. The active array contains a plurality of integrated circuits devices having operational functions. The guard array abutting an outer peripheral portion of the active array contains a plurality of transistors for protecting the plurality of integrated circuits devices from latch up. In general, the active array can be functional circuits like a memory array or a read only memory (ROM) array. The plurality of transistors in the guard array can be formed simultaneously with transistors in the active array and have same structure with the transistors.