The Epidemiological Unit was established in 1959 with assistance from World Health Organization (WHO) to strengthen surveillance of communicable diseases. Initially, the unit functioned with a WHO consultant and a national counterpart, who, after further training in epidemiology, was appointed in 1961, as the Epidemiologist of the Department of Health Services. .Prior to this, the functions of epidemiological surveillance were under the guidance of a Senior Medical Officer (Epidemiology)in the Department of Health Services. From its inception, the Epidemiological Unit worked very closely with the Public Health Veterinary Officer (now Director, Public Health Veterinary Services) and the Medical Statistician, and were all located at Chelsea Gardens,Colombo 3.

In the early 1970s, all three units were shifted to the Anti-Tuberculosis Campaign building at Deans Road, presently occupied by the Ministry of Health.

...By 1967, the Unit had expanded, two more Assistant Epidemiologists have ..been appointed during this period, both with specialized training in epidemiology.