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. In addition, introduction of Biochemistry courses with a link to the University of Glasgow through auspices of the British Council further enriched the courses offered by the Department.

Combining the fields of Management and Information Technology, the Department of Industrial Management meets the demands of global corporates. Its reputation for challenging the frontiers of knowledge with the support of an outstanding mix of academic faculty and world class facilities makes it an exciting, stimulating and fun place to learn and develop to your full potential in order to launch a successful professional career.

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). The Special Degree Programme was commenced subsequently with students specializing in one of the streams Pure Mathematics & Applied Mathematics, Pure Mathematics & Statistics and Mathematical Physics.

The Department of Microbiology offers Microbiology as a main subject for the B.Sc. (General) Degree and B.Sc. (Special) Degree programmes. It offers two postgraduate programmes as well, a Postgraduate Diploma/ Master of Science programme in Applied Microbiology and a Postgraduate Diploma/ Master of Science programme in Food and Nutrition. Opportunities for graduate students to read for M.Phil. and Ph.D. by research are also available at the Department of Microbiology.

The Department of Physics and Electronics offers two BSc Honours degree programmes; BSc Honours degree in Physics and BSc Honours degree in Mathematical Physics. BSc Honours degree programme in Mathematical Physics is offered jointly with the Department of Mathematics and it is unique to the University of Kelaniya.

The Department offers undergraduate courses in two separate academic disciplines viz. Botany, and Molecular Biology & Plant Biotechnology as well as opportunities for graduate studies in various subdisciplines. The innovative academic programmes conducted by well qualified and experienced academic staff provides students with the knowledge, flexibility and the skills needed for the 21^st century.

The Department of Statistics and Computer Science 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 and conducts two B.Sc.(Special) Degree programmes, one in Statistics and other in Computer Science. 

The Department of Zoology and Environmental Management contributes to four B.Sc. degree programmes, viz B.Sc. (General) degree programme in Biological Sciences, B.Sc. (Special) degree programme in Zoology,  B.Sc. (General) degree programme in Environmental Conservation and Management and B.Sc. (Special) degree programme in Environmental Conservation and Management. Department also offers an M.Sc. programme in Aquaculture and Fisheries Management.