The goal of the Interdisciplinary Longitudinal Study of Aging (ILSE) is to assess healthy and satisfying aging in middle adulthood and later life. In addition, this study compares adults from eastern and western Germany. The data for this study were collected between late 1993 and early 1996 as part of the first measurement point of the ILSE. Five-hundred and one participants from the Leipzig region were compared with 500 participants from the Heidelberg area on four specific dimensions: personality, cognitive functioning, subjective well-being, and health. Age differences were obtained for neuroticism, extraversion, openness, and agreeableness. Differences were also obtained in cognitive functioning and health. Regional differences between eastern and western Germany were obtained in the personality dimensions neuroticism, openness and conscientiousness, as well as in subjective well-being. Significant age by region interactions were obtained for openness and some of the cognitive measures, as well as for the physicians' health ratings of the participants, suggesting selective historical effects. The results are discussed with respect to functional abilities and levels of satisfaction in midlife, as well as with respect to regional differences that might be due to prior political system differences in the east and west.