Intermittent faults in combinational circuits may appear and disappear randomly; hence, their detection requires many repeated applications of test vectors. Since testing reduces the time available for computation, it is necessary to efficiently minimize the time required for a test, while still achieving a high degree of fault detection. This paper presents an optimal random test procedure to detect intermittent failures. The algorithm maximizes the probability of fault detection byoptimally choosing the input vector probabilities. Copyright © 1980 by The Institute of Electrical and Electronics Engineers, Inc.