Objectives To investigate the personnel allocation and workloads of the medical residents across the subspecialties of the Department of Internal Medicine at a tertiary hospital. Methods A cross-sectional survey was performed to investigate personnel allocation and workload. The resulting data were compared with the ministerial standard that regulates the training of medical residents. Results Aside from the subspecialty of Rheumatology, medical residents accounted for 40% to 70% of the total staff physicians. The faculty physicians accounted for only 20% to 50% of the total. When the non-faculty residents were not taken into account, each individual faculty physician took charge of between 5.3 to 15.5 beds across all the subspecialties. When only the non-faculty residents were accounted for, each individual resident took charge of 1.7 to 9.4 beds, 1.3 to 5.7 bed-days per day, and 5.8 to 17.3 patients per month. When both were accounted for, each physician was responsible for 1.3 to 5.9 beds, 1 to 3.6 bed-days per day, and 4.2 to 10.7 patients per month. In comparison with the ministerial standards, medical residents have managed more patients per month in the subspecialties of Nephrology, Respiratory Diseases, Digestive Diseases, Neurology and Infection.Fewer patients were managed in the subspecialty of Endocrinology. Conclusion The medical resident allocation is balanced across the subspecialties of the Department of Internal Medicine, although it is less stable. The total number of physicians is smaller than required, and physicians generally bear an overload of work. The number of patients managed by each individual resident is more than the requirement set by the ministerial standards, and has significant variations across subspecialties. Medical residents need to be allocated in accordance with the corresponding workloads.