What effect does a geropsychology practicum placement have on graduate students' knowledge of and attitudes toward older adults? Ninety psychology externs and interns were surveyed at the beginning of the training year and then 9 months later. About half of the trainees provided services in settings that served older adults, whereas the remainder did not. At the end of training, those with a geropsychology placement maintained higher interest in geropsychology, had lower negative attitudes toward older people, and had greater knowledge of mental health and aging than trainees without a geropsychology placement. There were no differences between the two placement groups in knowledge of general facts on aging and positive attitudes toward the aged. The implications of the findings for graduate program directors, training psychologists, and graduate students are discussed.