Total cord IgM measurements and an indirect γM-Fluorescent treponemal antibody (γM-FTA) test were performed on the cord sera of 43 seroreactive neonates to determine the reliability of each in diagnosing congenital syphilis. Thirty-three infants who did not have active disease had either a negative or minimally reactive (five cases) γM-FTA test. Four with definite and five with suspected active disease gave 3 to 4+ reactions. One infant who was suspected to have active disease was FTA negative. By titering the 3 to 4+ reactive sera, it was shown that this FTA test can detect considerably less than 1 mg/100 cc of antitreponemal IgM antibody. Total cord IgM levels were not reliably elevated in active cases. These results suggest that the γM-FTA test may prove to be an accurate additional way to diagnose congenital syphilis in the neonatal period even if the infant is asymptomatic.