Toxoplasma gondii is a ubiquitous parasite that can cause neurologic and ocular disease. We tested sera from 7,072 people≥ 6 years of age in the 2009–2010 National Health and Nutrition Examination Survey (NHANES) for immunoglobulin G antibodies and compared these results with two previous NHANES studies. The overall T. gondii antibody seroprevalence among persons≥ 6 years of age in 2009–2010 was 13.2%(95% confidence limit [CL] 11.8%, 14.5%) and age-adjusted seroprevalence was 12.4%(95% CL 11.1%, 13.7%); age-adjusted seroprevalence among women 15–44 years of age was 9.1%(95% CL 7.2%, 11.1%). In US born persons 12–49 years of age, the age-adjusted T. gondii seroprevalence decreased from 14.1%(95% CL 12.7%, 15.5%) in NHANES III (1988–1994) to 9.0%(95% CL 7.6%, 10.5%) in NHANES 1999–2004 to 6.7%(95% CL 5.3%, 8.2%) in NHANES 2009–2010 (P< 0.001 linear trend). Although T. gondii antibody presence is still relatively common, the prevalence in the United States has continued to decline.