 He was the President of the Sri Lanka Association for the Advancement of Science during its golden jubilee in 1994.At the time of his death he was the president of Infotel Lanka Society.Samaranayake was associated with the International Centre for Theoretical Physics (ICTP) in Trieste, Italy since 1969 as a UNESCO Fellow in Mathematical Physics (1969), IAEA Fellow in Mathematical Physics (1971), Associate Member (1972–1977) and a Senior Member since 1978.