Abstract. Objective: To test the feasibility of pneumococcal immunization in an ED. Methods: Cook County Hospital has an annual ED census of 120,000. Patients are 75% black and 15% Hispanic. Eighty-two percent of patients are uninsured. Seventy-three percent report no primary physician. Between May 27, 1997, and July 26, 1997, nurses had standing orders that patients meeting CDC-recommended criteria were to be offered pneumococcal immunization. Immunization was recorded in the system-wide registration computer. Results: During the study period, 1,833 patient screenings encounters (13% of all patients) identified 1,493 high-risk patients. Only 10% of screened high-risk patients reported previous pneumococcal immunization. 1,173 were immunized against pneumococcus. Median number of immunizations per nurse per shift was 1.62. Patient throughput was not altered. Conclusion: Pneumococcal immunization is both necessary and feasible in a busy ED serving patients with little access to other immunization services.