The Department of Chemistry was established with the inauguration of the Faculty of Science in September 1967. A new building complex built in 1996 facilitated the expansion of the Department. The courses offered by the Department expanded from B.Sc.(General) degree to B.Sc.(Special) degree in Chemistry and a two year M.Sc. Programme in Industrial and Environmental Chemistry.

The Department of Industrial Management (DIM) was formed with the objective of creating a discipline of science students who also possess management competencies. The initiative was to bridge the gap between management and information technology, integrating the two areas for the first time in the Sri Lankan University context. The department has gained acknowledgement for developing undergraduates who are able to challenge the established layouts of both academic and industry fields which itself is an establishment that challenges the conventional frontiers of knowledge.

The ‘Department of Mathematics’ has been functioning almost since the inception of the University way back in 1959, teaching Mathematics to the students in the Faculty of Arts. With the establishment of the Faculty of Science in 1967 the Department of Mathematics was formally established and since then has been teaching Pure Mathematics and Applied Mathematics as subjects for the Degree of Bachelor of Science (General).

Microorganisms, the “invisible task force”, drive the fundamental processes on which all life on earth depends. We are born into a world dominated by microorganisms and their activities are central to human welfare. As a consequence, we have innumerable intimate microbial associations; many enhance our lives, some are essential to our very existence, while others present us with potentially lethal challenges.

The Department of Physics which came into existence with the commencement of the Faculty in October 1967 is one of the eight academic departments that belong to the Faculty of Science of the University of Kelaniya. Since then, the Department has developed the academic programmes, with revisions of the syllabi at regular intervals and improvements of the laboratory facilities.

The Department of Plant and Molecular Biology, formerly known as the Department of Botany established in 1967, educates undergraduate students in current plant and molecular biological concepts and methodologies in the laboratory and the natural environment. In addition to the Botany discipline, a new discipline, Molecular Biology and Plant Biotechnology was introduced by the Department in 2003.

The Department of Statistics & Computer Science of the University of Kelaniya was established in July 1999 with the objective of meeting the ever-increasing Statistics and Computer Science education needs of university students in particular, and the academic and industrial community in general. At present the Department of Statistics & Computer Science offers Statistics and Computer Science as subjects for the B.Sc.(General) Degree Programme

The Department of Zoology and Environmental Management contributes to four BSc. degree programmes, viz BSc degree programme in Biological Sciences, BSc Honours degree programme in Zoology, BSc degree programme in Environmental Conservation and Management and BSc Honours degree programme in Environmental Conservation and Management.

The Software Engineering Teaching Unit (SETU) was established in September 2017 with the objective of preparing students for successful careers in the field of Software Engineering by providing a thorough understanding of engineering methods and scientific principles. The unit conducts the Bachelor of Science Honours in Software Engineering degree which is the only degree program in software engineering offered in the state university system in Sri Lanka.