All infectious disease consultations directed to the clinical microbiologists at the Queen Mary Hospital in February 1995 were analysed. A total of 95 written and 111 telephone consultations were received. Fifty three percent of the written consultations involved patients with persistent fever despite multiple antimicrobial therapy. Of all written consultations, gram positive bacteria, gram negative bacteria, and fungi were encountered in 39%, 31%, and 19%, respectively. The majority of written consultations (55%) were from surgical units. In contrast, 65% of telephone consultations came from medical and paediatric units. This study indicated that a wide spectrum of infectious disease problems--both diagnostic and therapeutic--were encountered by clinical microbiologists. The unique combination of laboratory skill and clinical infectious disease knowledge gives the microbiologist a distinctive advantage in assisting clinicians to provide optimal care to patients suffering from infection.