Only a few cases of pneumocystis pneumonia (PCP) in Cushing’s syndrome have been published in the literature so far. In the majority of these patients, the pneumonia occurred after reduction of the hypercortisolism with medicamentous treatment. We report two cases of PCP during conservative treatment of hypercortisolism. We describe clinical, imaging and laboratory findings in two patients and review published cases of pneumocystits pneumonia in Cushing’s syndrome. A 60-year-old woman and 20-year-old man with Cushing’s syndrome due to ectopic ACTH syndrome were treated at our department. Both developed pneumocystis pneumonia early after treatment with ketoconazole and ethomidate bromide had been introduced and the levels of cortisol rapidly decreased. PCP prophylaxis in patients with high cortisolemia should be started before treatment of hypercortisolism in current practice. Gradual lowering of plasma cortisol should also reduce the risk of infection by Pneumocystis jiroveci.