The present study was conducted to determine if 200 patients with silicone-gel implants demonstrated elevated levels of autoantibodies, compared with a similar group of 100 age-matched control subjects without breast implants. These results were then compared with 29 patients who had demonstrated implant rupture. Differences in the frequency of autoantibody levels were determined by the chi-squared test. Differences in autoantibody titers were determined by Wilcoxon's signed rank test. Differences were considered significant with p > 0.05. The prevalence of a positive antinuclear antibody (ANA) test (dilution 1:100) in the 200 patients with breast implants was 26.5% compared with 28% in the 100 control subjects. In 29 patients with implant rupture, only 17.2% tested ANA positive. These values were not significantly different. In addition, there were no significant differences between the ANA titers of positive patients in each group. In each of the three groups, all patients who tested ANA positive were analyzed to assess the frequency and titer of other autoantibodies, including anti-DNA, anti-cardiolipin, anti-SSA, anti-SSB, anti-SM, anti-RNP, and anti-Scl-70. There were no significant differences between the frequency or titer of any of these autoantibody levels in each of the three groups of patients. These studies strengthen the concept that there is no conclusive evidence that silicone-gel implants are related to the development of connective tissue disease.