Parathyroid imaging with 99m Tc-MIBI, introduced at the beginning of the 90's seems to be a promising method for parathyroid adenomas localization. The aim of the study was to assess the efficacy of parathyroid imaging with 99m Tc-MIBI for preoperative localization of parathyroid adenomas and to compare that method with the high-resolution ultrasonography. Thirteen patients with primary hyperparathyroidism of duration from 2 to 25 years were included in the study. The presence of parathyroid adenomas was confirmed by histopathology in all patients. The sensitivity for scintigraphy and ultrasonography was 92.8% and 78.5%, the number of false positive results was 0 and 2 and false negative-0 and 1, respectively. Parathyroid imaging with 99m Tc-MIBI is a useful method for parathyroid adenomas localization, and in contrast to ultrasonography its sensitivity does not decrease if a parathyroid adenoma is located ectopically. Nevertheless, because of the greater accessibility, lower costs and its simplicity ultrasonography should be used as a screening modality for parathyroid adenoma localization.