The course of latex sensitization is rarely documented, and only a few reports about the influence of prophylaxis in the occupational environment have been published concerning health care workers. Therefore we did a follow-up study in the high risk group of patients with spina bifida and evaluated the efficacy of latex prophylaxis. For this purpose we measured IgE antibodies (FEIA) against latex and inhalative allergens in the sera of 67 patients with spina bifida and reevaluated them 0.6 to 4.1 years later, having instructed the patients about prophylactic measures and established a latex-free environment for surgery of all spina bifida patients in our hospital. 37% of the patients did not develop latex antibodies during the follow-up period, 27% showed decreasing levels of antibodies (12% to non-detectable levels), 19% had an increase in latex sensitization (6% newly sensitized), and 9% showed no change in levels of latex antibodies. From our data it may be concluded that surgery without strict latex prophylaxis is the main cause of new sensitization and worsening of preexisting latex antibody levels. Mild sensitization can be reduced by prophylactic measurements to non-detectable antibody levels. With consistent prophylaxis, even symptomatic patients can be operated without risk of allergic complications or increasing antibodies.