Idiopathic talipes equinovarus (ITEV) is the most common form of clubfoot with a birth prevalence of 1 per 1,000 births. Serial casting and surgical correction impose a substantial financial burden on families and the health care system. While the etiology of ITEV is considered to be complex, the causes remain elusive. Genetic, maternal, and environmental factors have been suggested to play an etiologic role. This study was undertaken to determine the prevalence of ITEV and define maternal and environmental factors associated with ITEV in Texas from 1996 to 1999. Data on 682 cases of nonsyndromic ITEV were compared with all births (n = 923,543) in Texas during the same period. The overall prevalence and prevalence odds ratios (PORs) were calculated for gender, year of birth, public health region (PHR), race, maternal age, education, folic acid fortification, and parity. The overall prevalence of ITEV was 0.74/1,000 or 1/1,354 live births. Adjusted PORs were similar among blacks and US and foreign-born Hispanics (POR = 0.92, 95% CI = 0.69-1.21; POR = 0.99, 95% CI = 0.79-1.25; and POR = 0.94, 95% CI = 0.74-1.19), respectively, compared to whites. College education and higher parity were significantly associated with a lower risk of giving birth to offspring with ITEV. Babies born after folic acid fortification of grains had a very small decrease in ITEV that may be due to chance.