We attempted to determine the prevalence and clinical significance of rubber-specific IgE in a prospective case control study of 32 preoperative children with spina bifida, compared with 45 outpatient controls and 35 age-matched preoperative controls without spina bifida. A latex-specific radioallergosorbent test was positive in 11 of the 32 spina bifida patients (34%), compared with 1 (2%) and 4 (11%) of the respective controls (p less than 0.05). Within the spina bifida group 5 of 11 antibody-positive patients had a history of rubber-associated, intraoperative or otherwise idiopathic allergic episodes and 1 of 21 antibody-negative patients gave such a history (p = 0.012). Children with spina bifida have a significantly greater likelihood than controls of having IgE specific for rubber antigens. In addition, the presence of rubber-specific IgE is associated with a higher frequency of rubber-associated, intraoperative or idiopathic allergic reactions.