Many are calling for changes for internal medicine training, arguing that changes in the practice environment mandate changes in how the internal medicine residency is structured. Residency could be shorter, more conducive to role differentiation among general internists, and more supportive of subspecialization. Training could provide more experience in ambulatory care, multidisciplinary team-based care, chronic disease management, and quality improvement.The authors contend that the claim that internal medicine training ought to mirror internal medicine practice is mistaken. Many changes now proposed would likely damage if not destroy the consultant-generalist ideal of traditional internal medicine training which remains critical to effective medical care in the 21st century. The authors propose a model for training similar in structure but different in spirit from contending models. This model, like others, would involve a core experience in the first two years with tracking in the final year; unlike others, it would provide a conceptually coherent experience based on internal medicine's traditional ideal. Outpatient experience would be subsidiary to a predominantly inpatient experience, and it would be structured in blocks rather than continuity clinics. Twenty-first-century internists will continue to face what has always been the internist's task: the resolution of complex and ill-defined patient problems into proper diagnoses and therapeutic options. Contemporary internal medicine training must fit trainees for that task and must, thus, continue to offer the training experience necessary for the realization of the Oslerian ideal: a substantial apprenticeship taking care of inpatients with a wide range of medical illnesses. © 2008 Association of American Medical Colleges.