The association between optimism and health habits was evaluated among 31-year-old men and women (n=8690) born in Northern Finland in 1966. Both women and men above the upper quartile for optimism more often ate fresh vegetables and salads (women 76%/men 57%), berries (23%/9%), fruit (67%/42%), low-fat cheese (25%/16%) and salad dressing (15%/17%) than those below the lower quartile (56%/31%, 14%/5%, 52%/26%, 18%/10% and 10%/5%, respectively) with women in higher proportion than in men in each case. Pessimism was associated with infrequent consumption of foods rich in fiber and salad dressing and the proportions of high consumers of alcohol. Proportion of subjects with BMI of 30.0 kg/m2 and above and that of current smokers were higher among the pessimists than among the optimists. Thus lack of optimism is associated with a cluster of unhealthy dietary and other habits. This may at least partly explain the positive association of optimism with health found in previous studies.