a mathematical-statistical model was calculated by means of the multivariade discriminant analysis (p <0,05) to a sample of 76 workers, to differentiate the exposed workers and not to night shift work, basing us on the expression of the risk factors related with the gastroduodenal peptic ulcer and the subjetive perception of adaptation to the type of shift work was determinated in comparative form betwen groups. the study design was analytic of traverse court. the instruments applied to explore the factors of risk were: factors of individuality, personality, symptomatic scale of stress, exploration of labor fatigue and labor situation. the analogical-visual scale was applied to evaluate the subjetive perception of adaptation to shift work. the calculated discriminant function had a capacity of prognostic of 86,8% and the subjetive perception of adaptation to shift work was bad in 43,4 % of the sample without any significant differencies betwen groups. this result can constitute a first step in the strategy of prevention of this affection in our workers and keep alert about impact of psicological variables as subjetive perception of adaptation to shift work in that desease.