SUMMARY: Using an in vitro method, some factors affecting the attachment of a strain of lactobacillus to chicken crop epithelial cells have been studied. Time of contact beyond 10 min, pH value, age or growth temperature of the bacterial culture, or nature of the energy source in the growth medium had little or no effect on attachment. Heating to 100 °C for 10 min, or treatment with EDTA or surface active compounds was also without effect. Treatment with sodium periodate markedly decreased adhesion, proteolytic enzymes had a smaller effect but wheat germ lipase was completely inactive. The pronounced inhibition of adhesion periodate suggested the involvement of carbohydrate. However, enzymes known to attack carbohydrate substrates were inactive in reducing adhesion. Concanavalin A, which binds specifically to certain sugar residues, reduced attachment. It is suggested that these concanavalin A receptors on the lactobacillus are responsible for its attachment to crop epithelial cells.