We determined the association between T. gondii seropositivity and a history of sexual promiscuity. The study included 3933 people (mean age: 41.81 ± 14.31 years) who attended public health facilities. Face-to-face interviews were used to collect data. Enzyme immunoassays were used to determine anti-T. gondii IgG and IgM antibodies. Anti-T. gondii IgG antibodies were found in 57 (18.1%) of 315 individuals with sexual promiscuity and in 374 (10.3%) of 3618 individuals without this practice (OR: 1.91; 95% CI: 1.41–2.60; p 150 IU/mL) levels of anti-T. gondii IgG antibodies were found in 29 (9.2%) of the 315 participants with sexual promiscuity and in 167 (4.6%) of the 3618 participants without this history (OR: 2.09; 95% CI: 1.38–3.16; p = 0.0003). The association of sexual promiscuity with T. gondii seropositivity and serointensity was observed in men but not in women. Sexual promiscuity was associated with T. gondii seropositivity in all age groups studied (≤30 years, 31–50 years, and >50 years) and with T. gondii serointensity in two age groups (≤30 years, and >50 years). No difference in the frequencies of anti-T. gondii IgM antibodies among the groups was found. Our findings indicate that T. gondii seropositivity and serointensity are associated with sexual promiscuity.