Treatment of prolactin-secreting pituitary adenomas by dopamine agonists is highly effective and currently is used as basic treatment in most cases, however, literature sources practically do not contain data about possible complications of this therapy. We described a total of 11 cases of deterioration due to primary treatment of macroprolactinomas by cabergoline in the series of 176 patients. The first group included patients with enlargement of the tumor producing deterioration of the symptoms (onset of visual disorders and/or cephalgia). This occurred in 3 (1.7%) cases due to intratumoral hemorrhage or cystic transformation, and in 1 (0.6%) case as a result of growth of cabergoline-resistant tumor. The second group was made up of 6 (3.4%) cases of nasal CSF leak which developed within 3 to 6 weeks after start of treatment. All patients with CSF leak had adenomas with high sensitivity to the drug which produced rapid and significant shrinking of the tumor. The third group was presented by the single case (0.6%) of visual deterioration due to development of empty sella syndrome with dislocation of chiasm and optic nerves into sellar cavity.