The Department of Medicine was started in 1913 under Col. C.A. Sprawson. Initially the staff consisted of a Professor of Medicine, a lecturer and 2 part time physicians. The outpatients was manned by the Lecturer in Medicine, a post filled with great distinction by Late Dr. H.Sahai. An Infectious Diseases Hospital run by the Municipal Board and a Leprosy Hospital were attached to it. From 1946 onwards there has been an all round expansion of the department. From 62 beds in 1932, the bed strength has  grown to over 200.  The department was shifted to the new site - the Gandhi Ward in 1952. Prof. BB Bhatia encouraged research and investigation laboratories as an integral part of the Department and the Cardiology, Neurology, Hematology, Respiratory and Gastroentrology Laboratories were started in his time. In 1964, the Experimental Medicine units and a Human Metabolism laboratory came up under Prof. SS Misra .

Cardiovascular facilities - External pacemaker, vectorcardiography, ballistocardiography, apexcardiography, phonocardiography and cardiac catheterisation were started under the supervision of Prof. OP Tandon. A 10 bedded Clinical Pharmacology Unit was sanctioned by the Council of Scientific and Industrial Research (CSIR) in 1971. The Dialysis (Nephrology), Endocrinology and Coronary Care units came up under Prof. NN Gupta in the 1970s. The Units of Cardiology and Neurology were separated as independent departments also under Prof. NN Gupta. In 1984, Prof. RN Misra established the units of Intensive Care Medicine and Gastroenterology. A unified Admission Ward was renovated and commissioned in 2004 under Dr CG Agarwal. The Department of Rheumatology has separated in 2006.

At present the Department of Medicine is headed by DrRC Ahuja and has 250 beds distributed in 7 wards and ICU. There are 5 male wards and 2 female wards.