Prolactinomas are the most frequent pituitary adenoma. Their diagnosis follows clear and increasingly simple rules. Their severity depends on their size. Microadenomas are benign and nonaggressive; inducing gonadotropin insufficiency, they present endocrine problems and have harmful consequences on fertility and on overall health status. Treatment is simple, with D2 agonists showing remarkable efficacy as first-line therapy. This treatment may be chronic, sometimes only sequential, but should allow the patient a completely normal life. Several difficulties persist: macroprolactinomas may behave as aggressive tumors with their own complications. Some adenomas, even small ones, are resistant to D2 agonists, and their treatment has not been codified. Finally, as for all chronic diseases, long-term success depends largely on the information provided to the patient and the patient's adherence to treatment.