The role and timing of urodynamic studies in infants with congenital spinal dysraphism are controversial. We reviewed 64 consecutive infants with a mean followup of 28 months who underwent video urodynamic study when they were less than 1 year old (50 of the 64 patients were less than 3 months old). A previously reported video urodynamic "hostility score" from 0 (best) to 10 (worst) was given to each study and compared with the outcome of the upper urinary tract and subsequent urodynamic studies. A larger fraction of these children with high hostility scores (5 or greater) had upper tract deterioration (39%) compared to those with low hostility scores (9%). Moreover, 6 of 14 patients in the low hostility group who underwent repeat video urodynamic studies after age 1 year had high hostility lower urinary tracts. We conclude that urodynamic studies during and after the first year of life are useful in the appropriate urological evaluation and management of infants with spinal dysraphism.