Obesity has been associated with poorer performance on the Grooved Pegboard (GP) among healthy older adults. The GP is widely used in South Africa, among others for the assessment of HIV Associated Neurocognitive Disorders. Obesity is growing among the younger adult population inSouth Africa, which is the group also most at risk for HIV. It is not clear what the interaction between body mass and GP performance would be among a group of healthy younger adults. This study investigated whether body mass might affect fine psychomotor skills. A sample of 850 healthy adults (20 - 49 years) completed the GP and had their Body Mass Index (BMI) calculated. The relationship between GP and BMI was examined using ANOVA and correlation coefficients. The expected gender differences in GP performance found elsewhere were demonstrated in this sample. No significant interactions between BMI categories and GP times were found, and no significant correlations between BMI continuous scores and GP times were found either. In spite of the presence of a wide weight spectrum among the participants and the absence of any history of known medical disease, the lack of significant BMI-GP interactions suggest that the effect of BMI may generally be discounted when interpreting GP results.