Voids in impressions made by five automixed addition silicone elastomers with and without intraoral delivery tips were investigated. The number of voids were counted at a predetermined site on 3 days. Hand-mixed impressions of the automixed materials were made for comparison. There was no statistically significant difference in the mean number of voids produced in each automixed silicone dispensed with the use of intraoral delivery tips and the number of voids produced without the use of the tips. However, there were significant differences in the number of voids among different materials. the rank order of the automixed silicone elastomers was fairly consistent, with Express producing the highest and Reprosil the lowest number of voids. Automixed silicone materials should only be prepared by automixing for optimal results.