A synthetic‐work approach was employed in an investigation of the effects of 90‐dB continuous and periodic 96‐dB intermittent broad‐band noise on human performance. Ten Navy and Air Force ROTC cadets worked the tasks of a multiple‐task performance battery (MTPB) 12 h a week (in three, 4‐h sessions) during a 4‐week training period. Subsequently, they were required to work 4 days, 8 h per day on a split‐shift schedule during the presence of noise, and finally, work 2 additional days on the same split‐shift schedule under quiet conditions. Mean percentage of baseline performance (a composite index of performance) was enhanced by a periodic 96‐dB intermittent noise, and the extent of the effect varied as a function of the number of tasks concurrently performed in the work situation. On the other hand, 90‐dB continuous noise neither enhanced nor degraded performance. [Research supported by the U. S. Army Behavior and Systems Research Laboratory, Army THEMIS Contract; and by U. S. Army Medical Research and Development Command.]