This study was undertaken to determine the effects of computer-aided instruction on mathematics performance of pupils at the Grade 4 level in Region 5. This focus was due to the trend of poor performances in mathematics at the National Grade 4 assessments for the past 5 years. Four intact Grade 4 classes in two primary schools were used in this study. Two classes were used as experimental group and the other two as control group. The Quasi Experimental, Nonequivalent Control Group design was employed for this study. The instrument which was used for data collection was a teacher-made test. The reliability coefficient of the instrument was 0.553, significant at alpha 0.01. The findings of the study indicated that there was a significant difference between the academic performance of pupils in mathematics who were taught using computer-aided instruction and those who were taught using the traditional method of teaching. Second, there was a significant difference between the academic performance of male and female pupils who were taught using computer-aided instruction and those who were taught using the traditional method of teaching. In addition, there was a significant difference between the academic performance of lower- and middle-income pupils who were taught using computer-aided instruction and those who were taught using the traditional method. Based on the findings of this study, some recommendations were made and among such were that computer-aided instruction should be integrated into the teaching of mathematics at the Grade 4 level in the area of study.