ObjectiveTo determine the feasibility of laboratory reporting of infectious diseases and to compare the value of this system with the existing medical practitioner notification system.DesignA sample of notifications was selected from medical practitioner notifications and was compared for both completeness and timeliness of notification with a sample of notifications obtained through the Laboratory Infectious Diseases Surveillance Project.SettingThe New South Wales Health Department and the Public Health Unit of the Eastern Sydney Area Health Service.ParticipantsMedical practitioners forwarding notifications of infectious diseases to the New South Wales Health Department and laboratories participating in the Laboratory Infectious Diseases Surveillance Project.Main outcome measuresWe counted the number of infectious diseases reported by medical practitioners and participating laboratories and estimated the proportion of these diseases which were common to both sources of data. We also estimated the time taken between the diagnosis of a notifiable infectious disease and the receipt of the notification by the Medical Officer of Health.ResultsThere was substantial underreporting of notifiable infectious diseases by medical practitioners. During the study there were 461 cases of a notifiable disease reported by either medical practitioners or by participating laboratories. Of these cases, 75% were reported only by laboratory staff, 20.2% were reported by medical practitioners alone and 4.8% of cases were reported by both laboratory staff and medical practitioners. The Medical Officer of Health received the reports from the participating laboratories within a significantly shorter time than the notifications from medical practitioners.ConclusionThe use of infectious disease notifications by laboratories can substantially improve the surveillance of infectious diseases.