Background The majority of pituitary adenomas are sporadic, but about 5% of them occur in a familial setting, predominantly in multiple endocrine neoplasia type 1 and Carney complex. Familial isolated pituitary adenomas (FIPA), unrelated to the syndromes mentioned above, were also described. The clinical course of FIPA differs significantly from sporadic cases, and is characterized by a larger tumor size, more aggressive course and younger patients’ age at the moment of recognition. Objectives The aim of this retrospective study is to present 4 families in which two closely related people were diagnosed with pituitary adenomas. Probably these cases are clinical manifestations of FIPA. Material and methods Eight patients within four families, presenting with anterior pituitary tumors were described. The authors analyzed medical and family histories of the patients, their imaging pictures (pituitary MRI/CT) and hormonal tests. Results Family 1.: two sisters with acromegaly in the course of macroadenoma. Family 2.: two brothers with clinically nonsecreting macroadenomas. Family 3.: father and daughter with clinically nonsecreting macroadenomas. Family 4.: young man with acromegaly caused by macroadenoma and a daughter of his mother`s sister with microprolactinoma. Conclusions. Familial isolated pituitary adenomas are more common than it was previously thought, therefore, specific questioning regarding family history should be a part of the workup of all patients with pituitary adenomas. Genetically induced pituitary tumors often have aggressive behavior in terms of tumor expansion and resistance to different treatment options and often involve a multidisciplinary approach that combines endocrine, neurosurgical, and radiological specialists.