I examined correlates of Negative Affect (NA) and Positive Affect (PA) through both within- and between-subjects analyses. Eighty subjects completed a daily questionnaire for 6-8 weeks. Each day they rated (a) their mood, (b) the extent to which they suffered from various minor physical problems, (c) their level of stress, (d) the time they spent socializing, and (e) whether or not they had exercised. Subjects also completed several trait tests measuring their general affective level, frequency of health problems, and social tendencies. A between-subjects analysis showed the expected pattern: Level of physical complaints and perceived stress were correlated with individual differences in NA but not in PA, whereas social indicators and frequency of exercise were related only to PA. The within-subjects results generally exhibited a similar pattern: Social activity and exercise were more strongly related to PA, whereas perceived stress was highly related to NA. However, the most significant finding was that, contrary to prediction, health complaints were as strongly related to intraindividual fluctuations in PA as in NA. Possible interpretations of the observed correlates of NA and PA are discussed.