Semi-quantitative and qualitative bacterial assessment of the vaginal and cervical flora of a total of 202 women was carried out over a period of six months to determine the bacterial flora in three groups of women and changes caused by prior use of antibiotics. The number was made up of 32 healthy volunteers, 80 women with gynaecological problems and 90 women with gynaecological infections who had had antibiotic treatment prior to this study. Standard methods were used for the investigations. Five main genera of anaerobic bacteria were isolated from all patients. They included, the Bacteroides spp., Prevotella spp., Porphyromonas spp., Peptostreptococcus spp. and Clostridium spp. Five non-sporing gram negative anaerobic bacteria constituted the bulk of the flora including Prevotella bivia, P. disiens, P. melanogenica, P. asaccharolytica and B. fragilis. The predominant flora was P. bivia occurring in 61 pc of cervical swab specimens of the 80 women with proven gynaecological infections who had not used antibiotics and accounting for 27 pc of the total number of Gram-negative anaerobic bacteria isolated. Escherichia coli and Staphylococcus epidermidis were the most frequently encountered aerobic bacteria. The semi-quantitative counts of the different bacterial species in the patient group were significantly higher than in the control group of healthy individuals (p < 0,025). Similarly, prior antibiotic administration significantly reduced the population and quantitative count of the anaerobic bacteria.