Unity of form represents the extent to which visual objects on the screen are related in size. High levels of unity of form can be achieved by using objects with similar sizes on the screen and/or by reducing number of objects on the screen. Findings of earlier observational studies suggested that unity of form has significant effects on perceived visual aesthetics of website design in the case of highly symmetrical designs. The purpose of this study is to verify these findings. This study was conducted to systematically test effects of number of objects and number of different sizes of objects on perceived visual aesthetics of website design under the condition of high level of symmetry. Results showed that both factors have significant effects on perceived visual aesthetics. Designs with lower levels of both factors produced better visual aesthetics.