In a group of 21 patients sent by endocrinologist for antihyperthyreosis therapy with radioactive iodine, we calculated and compared the weight of the thyroid gland by quantitative static scintigraphy, using two computed parameters--according to surface and volume of the gland. Statistically we came to the conclusion that weight of the thyroid gland calculated on the basis of surface gives significantly higher values than calculation by the use of volume. The calculation of weight of the thyroid gland using the surface of scan image is recommended, while quantitative static scintigraphy increases the standardisation of the procedure very much.