A cytological and bacteriological examination of uterine lavages of 264 cows from herds with fertility disorders (without convincing pathological findings) helped to determine the clinical diagnosis in a more exact way. In 41.67% of the cases, mucosal metritis was cytologically proved. Bacterial contamination of the urerine medium was observed in 83.71% of the cases. The result of bacteriological examinations of uterine lavage and cervical smear brought about various findings in 77.27% of the cases. The bacteriological contamination rate of the uterine medium without metritis was highest in the follicular phase. Both the cows suffering from metritis and in cows without any changes due to metritis, common, conditionally pathogenic microflora was found (with the exception of several cases) the etiocausal effect of which on the metritis origin and decreased fertility could not be, in general and for certain, proved.