This paper considers autocorrelation testing for the detection of single stuck-at faults on non-syndrome testable input lines of an internally unate combinational network. The question of an autocorrelation test covering more than one input fault is considered. Also a test circuitry which requires only 2ninput assignments for ann-input system is presented. The work of this paper is an extension of previous work on autocorrelation testing by Eris and Muzio [6].