In a study to determine the epidemiological situation of N. gonorrhoeae (NG) in Switzerland, 149 strains isolated from different regions over the period September 1981 to February 1982 were analyzed for sensitivity to various antibiotics (minimum inhibitory concentration [MIC] for penicillin G, ampicillin, cefuroxime, tetracycline, thiamphenicol, and spectinomycin) and for their auxotype. From the results obtained it can be concluded that (1) the PPNG (penicillinase producing NG) strains are not a problem at present in Switzerland; (2) 15% of the non-penicillinase producing NG strains are "less sensitive" to penicillin G (MIC equal to or greater than 0.5 micrograms/ml); (3) sensitivity level of the NG strains to the various antibiotics assayed and the auxotypes do not show any significant peculiarity when compared to the data reported in other countries; (4) penicillin G should still be used as the first choice antibiotic at present in Switzerland, with spectinomycin, thiamphenicol and cefuroxime as second choice antibiotics; (5) when compared according to the geographical origin of their isolation, the NG strains show specific peculiarities, a fact which could lead to an antibiotic therapy policy more suited to specific regions.