Clinically unsuspected pituitary lesions are demonstrated by magnetic resonance imaging in approximately 10% of the general adult population, characterizing the so-called pituitary incidentalomas. Their natural history is not yet completely established. Despite being typically small (<10 mm in the greatest diameter) and clinically silent, some pituitary incidentalomas may be hormonally active or cause mass effects by compressing neighboring structures. Furthermore, a minority of these lesions, particularly those greater than 10 mm (macroincidentalomas) may grow over time; hence, longterm follow-up is necessary. Therapeutic interventions are indicated for lesions that are hormonally active (use of dopamine agonists or transsphenoidal resection) or for those that cause mass effects or increase in size during the follow-up (transsphenoidal resection). Significant suprasellar extension or hypopituitarism may be additional indications for surgical treatment even in the absence of chiasm compression.