Among 258 patients operated on for secondary hyperparathyroidism (HPT II) from 1971 to 1988, a total of 33 had one or more reoperations for persistent or recurrent HPT II. These reoperations did not induce any mortality or significant morbidity. After inadequate parathyroidectomy (25 cases), 15 patients were reoperated. Twelve of these had undergone initial surgery at another institution. Three patients died of causes unrelated to their HPT II. The other 12 patients are disease-free. After successful subtotal parathyroidectomy (79 cases), 2 patients (2.5%) had a recurrence 5 and 6 years later, respectively. Currently, the 2 patients remain disease-free. After total parathyroidectomy with autotransplantation (152 cases), 16 patients (10.5%) had reoperations on the grafts. The mean time before reoperation was 2 1/2 years. Hypertrophy of grafted fragments was observed in 4 cases (2.6%), but only 2 of these 4 patients were cured by removal of the grafts. Residual parathyroid tissue or a supernumerary gland in the neck or the mediastinum was suspected in 5 patients, but this could not be confirmed because one had already been reoperated on in the neck without success, another still refuses reoperation, and 3 died. In 6 other patients, the recurrence was debatable and HPT II was not confirmed. In the last 3 patients, the diagnosis was incorrect and aluminum intoxication was proved later. Results of reoperations for persistent or recurrent HPT II depend, first, on a correct diagnosis.(ABSTRACT TRUNCATED AT 250 WORDS)