A total of 50 patients suffering both from atopic skin disease and different clinical forms of blepharitis have been included in this study. Microbiological investigations (for bacteria and fungi) of the lid margins were performed in all cases. In 21 (42%) of the patients an ulcerative blepharitis which heavily involved the follicles of the lashes was diagnosed. The remaining 29 cases presented with blepharitis of the squamous type. The cultures revealed that 19 of the 21 patients with ulcerative blepharitis were found to grow Candida species, whereas fungi could not be detected in any of the other cases of blepharitis. The frequencies of concomitant bacterial organisms found in the cultures were similar in both groups. As atopic patients are known to exhibit a defect in their cell-mediated immunity and possibly also a defective IgA antibody response it is a widely accepted assumption that these immunological changes are contributing factors to the development of a localised inflammation of the lids which is initiated by a variety of micro-organisms. We postulate that when Candida species happen to coincide with severe inflammation in atopic patients a blepharitis of the ulcerative type will develop or deteriorate thereby implying that these microorganisms may play an important role in the development or deterioration of this severe chronic inflammation. It is therefore advisable to perform repeated scrapings and cultures in every case of recalcitrant blepharitis.