The authors draw attention to the possible presence of hyperthyroidism associated with the syndrome of so-called partial (hypophyseal) resistance to thyroid hormones in the absence of a pituitary tumour, based on the experience assembled during the follow-up of a 35-year-old female patient. The syndrome is characterized by elevated T4, T3 and also TSH levels. The syndrome of partial resistance to thyroid hormones differs from that of generalized resistance by a non-familial incidence and the presence of mild hyperthyroidism; from a pituitary tumour with overproduction of TSH it differs by a positive TSH response to TRH stimulation and the ratio of alpha- and beta- sub-units of TSH and also by the absence of pathological changes on the sella turcica during graphic examinations. Treatment by common antithyroid drugs does not lead to clinical improvement nor to normalization of T4, T3 and TSH levels. The syndrome is rare and according to, so a reports in the literature, the views on its cause and methods of long-term treatment are not uniform.