This second paper of the National Study of Internal Medicine Manpower describes the differing environments of residency training programs. Using previous studies as prototypes, the authors apply factor analysis to data from questionnaires returned by residency training directors and residents to illustrate the myriad interrelations within training programs. The most important result of this study is the demonstration that the largest residency programs have the most subspecialty programs, and their residents are more likely to pursue subspecialty fellowships after completing their third residency year. However, preliminary findings show no associations between the typology (typologic categories of residencies and their trainees) used and desired practice locations in states having few physicians relative to the population or in states with fewer urban inhabitants. The typology also does not predict the future practice aspirations of residents who are more likely to care for the poor or minority populations. A separate set of factors, possibly unrelated to training environments, will help to predict such career outcomes. Further specification of these factors will be the subject of a later paper in this series.