During an 18-month period, data from all patients in whose care our infectious diseases (ID) service was involved, were recorded in a computerized database. A total of 4184 new consultations was recorded. The consultations were solicited by the patients' physicians in 3326 cases (80%) and initiated by the ID service in the remainder. The purpose of the consultations was diagnosis (14%), therapy (39%), both diagnosis and therapy (40%), and prophylaxis (6%). Two thousand and ninety-four consultations (50%) were performed at the bedside, and the others by personal or telephone discussion. ID consultation was given in more than 10% of admitted patients in six departments, 46% of the admissions in the ICU, and 6.9/100 hospitalized patients. Recommendations included: antibiotic manipulation (i.e., initiation, change or discontinuation of antibiotic treatment) (51%); performance of tests (13%); performance of diagnostic or therapeutic procedures (5%); prophylaxis (4%) or no change in management (26%). Analysis of the solicited vs unsolicited consultations and of the bedside vs telephone consultations revealed that sub-groups of consultations differ significantly from each other in many aspects. Recording of consultations enables the ID service to evaluate its activity and to direct efforts to departments with high rates of infectious diseases and/or antimicrobial usage.