We studied certain indicators of the speed with which infectious diseases were notified and epidemiological case records carried out by public health workers for notifications with and without inclusion of laboratory test results. The notification records for brucellosis, dysentery, typhoid fever, viral hepatitis, meningococcal meningitis, and pulmonary tuberculosis in the province of Barcelona between 1982 and 1986 have been reviewed. For each disease notified the time lapse between the onset of symptoms and notification (Delay 1), between notification and implementation of the epidemiological investigation (Delay 2), and the sum of both time lapses (Delay 3) were calculated. In all diseases (with the exception of meningococcal meningitis) when significant differences in delays were noted, the longest were found in those notifications that included laboratory data in the epidemiological investigation. This means that the provision of laboratory data makes the process of notification slower (Delays 1, 2, and 3). Both notification when laboratory results are available and the inclusion of laboratory data in the epidemiological investigation, have a negative influence on the speed of the statutory notification process.