The purpose of this quasi-experimental study is to evaluate the overall effect of practical work on students' academic attainment in science. Participants were selected from tenth grade students (chemistry and biology) and eleventh grade students (chemistry), then divided into groups. The control groups were taught using traditional methods of teaching science, while the same content was given to the experimental groups using intensive practical work. Pre and post-tests were given to all groups. The mean score comparison revealed a significant difference in the attainment scores of the experimental over the control groups. It is thus recommended that students be given ample opportunity to be engaged in practical lessons in secondary schools. This entails that the administration of schools supplies their labs with all equipment needed for practical work to be effectively implemented.