The purpose of this study was to identify and investigate the main factors involved in the design of computer graphic user interfaces (GUI), commonly known as computer icons. Nineteen elements related to icon design were extracted from the principles, criteria and guidelines for GUI design. Forty-three Taiwanese designers working in computer GUI design were recruited to rate the importance of each design element.Results from the principal components analysis showed that the subjects' importance ratings for computer icon design elements were affected by five factors: styling quality, message quality, meaningfulness, locatability, and metaphor. In addition to comprehensibility and identifiability, which previous results have found to be important icon design considerations, styling quality may also be important. Analysis of variance of the importance ratings for elements within each factor found that meaningfulness and locatability were more important than styling quality, message quality and metaphor. Finally, the correlation results indicated that neither computer GUI design experience nor the designers' gender were related to importance ratings for the icon design elements.