Effects of past, current, and anticipated naturalistic daily stressors and of affect on salivary cortisol levels were examined. Participants (120) reported on stressors and affect 6 x /day in response to a preprogrammed wristwatch. Twenty min after each assessment they took a sample of saliva for cortisol analysis. Both the experience of a current stressor and anticipating a stressor were associated with increased salivary cortisol levels. Average increases in cortisol were relatively low, but inter-individual variability in this response existed. Stressors also were associated with lower positive affect and higher negative affect. Negative affect was associated with higher cortisol levels and positive affect was associated with lower cortisol levels. Daily stressors were not significant predictors of cortisol secretion when affect was controlled. Momentary assessment of daily stressors and of salivary cortisol proved to be a useful tool for examining psychoendocrinological processes in the natural environment.