The study investigated effects of computer-laboratory-simulation on achievement and retention in Physics, specifically in the latent heat of fusion of ice, among colleges of education students in Niger state. The design for the study was quasi-experimental research design, specifically, pre-test, post-test non-randomized, non-equivalent control group design. Four research questions and corresponding null hypotheses were formulated to guide the study. The population of the study consists of all Nigeria Certificate in Education (NCE) level one Physics students in Colleges of Education during the 2022/2023 academic session in Niger state. The sample of the study consists of 57 (30 male and 27 Female) level one physics students in Niger state, two intact classes were used. The instrument used in this study was Physics Practical Achievement Test (PPAT) as a test instrument. The PPAT comprised of 25-item multiple-choice type questions, validated by experts and its reliability coefficient was calculated to be 0.82, using Kuder-Richardson (KR20). Data gathered were analyzed using Mean, Standard Deviation and Independent t-test statistics. The study revealed that experimental group achieved more than the control, and the difference in the achievements was statistically significant t(67) = 3.21, p=0.002, (P0.05). It was therefore concluded that the students’ achievement and retention are better attained when simulation method is used in teaching. It was recommended that science teachers should be trained to produce indigenous Simulation Software. Keywords: Physics, Latent Heat, Computer Simulation, Achievement, Retention