In Munich 169 isolates of Neisseria gonorrhoeae were investigated with respect to nutritional profiles (auxotypes) and antibiotic susceptibility. Of the 165 penicillin-susceptible strains 97 proved to be prototrophic (auxotype 1), 42 proline-dependent (auxotype 2). Only 3 arginine-, hypoxanthine- and uracil-dependent strains (auxotype 14) were found. A total of 10 different auxotypes were identified among the non-penicillinase-producing strains and one among the penicillinase producers. The minimal inhibitory concentrations of penicillin G ranged from 0.01 to 1 microgram/ml, those of cefuroxime from 0.001 to 4 mg/ml; tetracycline and kanamycin had a narrow spectrum of effective concentrations, from 0.25 to 8 micrograms/ml and from 4 to 64 micrograms/ml respectively. The type 14 strains showed the well-known high susceptibility to penicillin G.