The relationship between visual fatigue and occupational stress was studied in video display terminal (VDT) operators. Clerical workers (90) from 15 different offices and 31 employees of a centralized library cataloging service were interviewed and an industrial visual screening device was used to obtain measures of acuity, lateral phoria, and vertical phoria at both near (0.35 meters) (m) and far (6.1m) optical distance. The subjects also filled out a 37 item checklist of moods and physical or mental stress symptoms. Lighting complaints were made by 37 percent of the subjects. Over half the total number of subjects mentioned some aspects of general stress and fatigue associated with their work. The correlation between VDT time and the light factor was moderately large and highly significant with complaints about visual fatigue and lighting increasing as time on the VDT increased. Optometric screening data from 23 subjects revealed no significant effects in any of the six vision tests due to time of day or day of week. Subjects reported more physical symptoms after work than before with the largest increases in physical symptoms caused by eye strain, blurry vision, neck and shoulder problems, focus problems, and lower back problems. The authors conclude there was a significant correlation between visual fatigue and inadequate lighting among VDT operators. There was an insignificant correlation between physical and mental stress and visual fatigue.