IgE-mediated sensitivity to natural rubber latex is being recognized more frequently among health care workers. Between January 1990 and June 1993, we evaluated 342 consecutive Mayo Medical Center employees who reported symptoms suggestive of latex allergy. All were interviewed and underwent puncture skin testing with extracts of rubber gloves. In some cases, latex-specific IgE antibodies were measured by immunoassay. One hundred four of the 342 employees evaluated (30%) were latex-allergic. Risk factors for sensitization included frequent use of disposable gloves, presence of prior atopic disease, and prior or current hand dermatitis. The peak onset of symptoms occurred in late 1989 and early 1990 and did not correlate with a peak in glove usage at our medical center, which continued to rise. Most sensitized employees (78%) reported contact urticaria from rubber gloves, and over two thirds also experienced allergic rhinitis, conjunctivitis, or asthma when working in areas where large numbers of gloves were being used. Sixteen episodes of rubber-induced anaphylaxis were documented in 12 employees; six episodes occurred after latex skin testing and were easily reversed with appropriate therapy. Our findings substantiate a local epidemic of latex allergy among medical center employees. Epidemiologic studies are needed to assess the effects of various interventions to reduce occupational exposure to latex allergens. Although prick skin testing with concentrated latex glove extracts presents some risk of systemic reaction, pending availability of commercial diagnostic extracts, such testing is generally safe when performed by skilled laboratory personnel. Skin testing is warranted to investigate health care workers suspected of being latex-sensitive.