Epidemiologic evidence does not support a consistently increased cancer risk among women with cosmetic breast implants, but few studies have assessed risk beyond 15 years. Swedish women who underwent cosmetic breast implantation for the first time between January 1, 1965, and December 31, 1993 (N = 3486), were followed through December 31, 2002. Cancer incidence was ascertained through the nationwide Swedish Cancer Registry. Standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) were calculated to compare cancer incidence of women with implants with women in the general population. Mean follow-up among women with breast implants was 18.4 years (range = 0.1-37.8 years). The incidence of breast cancer was below expectation (SIR = 0.7, 95% CI = 0.6 to 1.0), whereas lung cancer was above expectation (SIR = 2.2, 95% CI = 1.3 to 3.4). With respect to cancer overall and all other specific cancer sites, including brain cancer and sarcoma, non-Hodgkin lymphoma, and multiple myeloma, no statistically significantly increased or decreased SIRs were observed. Stratification by duration of follow-up revealed no statistically significantly increased or decreased SIR, with the exception of a two- to threefold excess of lung cancer among women followed for more than 15 years, which would be expected due to the high prevalence of smoking among the Swedish women with implants in our study.