In 22 patients with progressive endocrine ophthalmopathy (classes 4-6 according to Werner's scale and ophthalmopathy index at least 4 and evidences of infiltrative changes in retro-ocular tissues in computerised tomography, after achievement of euthyroid state) the titers of antibodies against thyroid membrane antigens (ATMA) were determined by Gardas and all. method. Control group consisted of 26 patients with Graves-Basedow disease without clinical signs of ophthalmopathy who were investigated for ATMA before and after conventional methimazole treatment. The determinations of ATMA were performed before treatment, after 3-4 weeks and subsequently once a month. ATMA's titers exceeding 1:1000 were found in 68% of patients with progressive infiltrative ophthalmopathy and in 77% of patients with Graves-Basedow disease without ophthalmopathy. The incidence of elevated ATMA titers during treatment of ophthalmopathy with supervoltage retro-orbital tissues irradiation with high dose of prednisone, decreased markedly in 6th month of treatment with subsequent increase to average 55% at the end of treatment what suggests the influence of therapy on antibodies production. The changes in the incidence of elevated ATMA titers during conventional Graves-Basedow disease treatment were different. No relations between increased ATMA titers and intensity of infiltrative ophthalmopathy and the course of treatment in the patients with ophthalmopathy were found.