Minimum inhibitory concentration (MIC) of penicillin was estimated for 25 strains of N. gonorrhoeae, isolated over a period of 10 months (September 1983 June 1984). In 16 d be strains, the MIC of penicillin ranged between 0.01ug/ml and 0.63 ug/ml and all were negative for penicillinase production. In 9 strains, the MIC was 1.25 ug/ml, and 5 of these strains produced penicillinase. Of these 5 penicillinase producing strains, 4 had MIC10 ug/ml and in one it was 2.5 ug/ml.