Routine testing of gonococci isolated from patients attending the Venereal Diseases Control Centre in Adelaide during the year July, 1974 to June, 1975, with a plate dilution method, showed that 93-8% of the 947 infecting strains were relatively sensitive to penicillin at a minimum inhibitory concentration (MIC) of 0-12 units/ml or less, and that 90% of the 648 strains tested were relatively sensitive to tetracycline at an MIC of 1-0 mug/ml or less. A small proportion only of isolates were relatively insensitive to penicillin and/or tetracycline. The routine treatment schedules which were used at the Centre proved adequate for infections over the whole range of sensitivities encountered. A significant proportion of the less sensitive strains were isolated from people infected in South-East Asia, most of whom had been inadequately treated there.