The aim of the study was to investigate and compare the type of resistance to antibiotics and plasmid profile of Shigellae sonnei isolated at epidemics of bacillary dysentery to determine which method was most reliable in the identification of epidemic strains of that bacteria. It was investigated 130 isolates of Sh. sonnei isolated from the stools of patients in 14 epidemics of bacillary dysentery in Yugoslav Army and citizens in period from 1987 to 1993 year. On the basis of identity of studied features of all isolates originated from one epidemic, epidemic strains of Sh. sonnei could be identified in 10 (71.4%) of 14 studied epidemics by means of plasmid profile, and in 8 (57.1%) epidemics by means of determination of resistance type to antibiotics. According to that, the method of plasmid profile analysis is more reliable in identification of Sh. sonnei epidemic strains compared to the method of determination of resistance type to antibiotics.