Using 1973–2000 mesothelioma incidence data released by the Surveillance, Epidemiology, and End Results Program in April 2003, the authors estimated the parameters of a birth-cohort and age model to determine whether previously reported patterns of mesothelioma in the United States have changed. Compared with analyses based on data through 1992, a slower decline was found in male cases immediately after a peak in 2000–2004, but no other notable changes in the time pattern were detected. Analysis confirmed that the annual number of male mesothelioma cases, which increased steeply from the 1970s through the mid-1990s, has leveled off in terms of both the age-adjusted rate and the absolute numbers of cases. After a peak of approximately 2,000 cases, a return to background levels is expected by 2055. The total projected number of male mesothelioma cases in 2003–2054 is approximately 71,000. The maximum lifetime risk for males, which occurs for the 1925–1929 birth cohort, is 1.8 × 10–3. The age-adjusted rate for females is constant, as are the female lifetime mesothelioma risk across birth cohorts (3.6 × 10–4) and the annual risk (3.9 × 10–6). The time pattern of cases for females supports the existence of a threshold exposure for mesothelioma and a quantifiable background rate.