This study explores interest in physics, chemistry and biology among school students in Kerala. It used a sample of 3236 (1659 boys, 1577 girls) students studying in upper primary to higher secondary classes. Three separate versions of scale of interest in science were used to quantify interest in science of upper primary, secondary and higher secondary levels. In order to make the scores from the three versions comparable, raw scores were transformed into standard scores. Among both girls and boys, interest in science topics is highest during primary stage than during secondary schooling. During upper primary schooling, interests in both physical and biological sciences are equal among girls, while boys have more interest in biology than physical sciences. During secondary schooling the difference between interests in biological science and physical science become more pronounced, while the reverse happens among boys. By higher secondary level, chemistry is the least liked science subject among both boys and girls, but girls like physics only as much as chemistry; while boys prefer physics much more than chemistry. Boys, more than girls, wanted to know more about physics topics whereas girls' interests lay more in the biological sciences; younger students expressed more positive attitudes toward science than did older students. The study concludes that as interest develops very early in life and influences students future choices, monitoring it should begin from primary school itself. Leaving it unnoticed in the developing stages is detrimental as, it would be quite difficult to make people appreciate science. (Contains 3 tables and 3 figures.)