The seasonal changes of the tissues of the glandular swollen thumbs of frogs were observed and measured. The swollen thumbs appear during breeding season. Thickness of the swelling is owing to the appearance of the papillary process on the epidermis and the development of the skin gland in the corium. The glands are alveolar and mucous glands. The gland epithelium is columnal and nucleus is in the base. The papillary process is present in May and June - the breeding season-butin July disappears and in September appears again, According to changes of the epidermis the glands of the corium increase or reduce their size and the length of the glandular epithelium. Strinctly,the change of the glands is present ealier than the changes in the epithelium.