To assess the utility of exfoliative cytology in the diagnosis of chronic conjunctivitis, we compared its findings with microbiological examination and established the correlation between cytology and microbiology in 32 patients with conjunctivitis lasting four weeks or more, with a nonspecific clinical picture. The material for cytology was collected by scraping and by imprint of the ocular surface on Millipore filter paper. The specimens were stained with Giemsa. Material for bacterial culture and fluorescent antibody test for viruses and Chlamydia were obtained at the same time. In 12 patients neutrophils predominated in cytology, in six eosinophils were found and in four there were more lymphocytes. One patient had a basophilic intracytoplasmic inclusion specific for Chlamydia infection. In eight patients coagulase-negative Staphylococcus species and in one Staphylococcus aureus were isolated, in two the fluorescent antibody test for Chlamydia was positive and in three for viruses. In all patients with a positive bacterial culture, a predominance of neutrophils was observed. All patients with a positive test for viruses had lymphocytosis in conjunctival scrapings. In two patients microbiology detected Chlamydia, but characteristic intracytoplasmic inclusions were observed only in one. Scrapings gave more specific results, that correlated well with microbiology in bacterial and viral infection, whereas the results of impression cytology showed minor metaplastic changes of epithelial cells that were nonspecific for the type of inflammation. Cytology remains a useful non-invasive tool and is an adjunct to clinical and microbiological examination. It proved especially helpful in allergic conjunctivitis.