There has been significant increase in the number of brucellosis cases admitted to our clinic within first 6 months of 1979. Since most of the cases were from Ayaş, Polatli and Oltan villages we visited Oltan and examined 97 persons 23 of whom had complaints of fever, arthralgia and sweating. In addition to previous 5 cases, 5 more patients were found to have antibody titers of 160-640. In the control group none of the randomly chosen outpatients had titers higher than 40. Three milk samples taken from 12 sheep also had antibodies against brucella. Six B. melitensis strains isolated from these and the other patients were sensitive to terramycin, rifampicin and streptomycin; but resistant to sulfonamide, chloramphenicol and clindamycin. Four of them were sensitive to bactrim and ampicillin. In this paper, the findings of 17 cases of brucellosis other than from those of Oltan have also been presented.