Craniosynostosis is a birth defect characterized by premature fusion of one or more cranial sutures. We describe the birth prevalence of craniosynostosis and related risk factors among infants born to residents of metropolitan Atlanta during 1989–2003. Data from the Metropolitan Atlanta Congenital Defects Program (MACDP) were used to identify infants with craniosynostosis. Case records with a code for craniosynostosis were reviewed to substantiate the diagnosis of craniosynostosis and to classify infants as having isolated craniosynostosis (no other unrelated major defects), multiple defects (one or more additional major, unrelated defects), or a syndrome (recognized or strongly suspected single-gene condition or chromosome abnormality). Vital records data on births of Georgia residents were used to analyze craniosynostosis prevalence by year of birth, maternal race and age, parity, plurality, and infants' sex, birth weight, and gestational age. We identified 281 infants born with craniosynostosis in metropolitan Atlanta during 1989–2003: 84% with isolated craniosynostosis, 7% with multiple defects, and 9% with syndromes. The birth prevalence was 4.3 per 10,000 births, results consistent with findings from other population-based studies using similar case definitions. Apert syndrome was diagnosed in 40% of the syndromic cases, and sagittal synostosis was diagnosed in 39% of the cases of nonsyndromic craniosynostosis. Maternal age 35 years or older, multiple birth, male sex, and birth weight >4,000 g were risk factors for craniosynostosis. Published 2008 Wiley-Liss, Inc.