Parlodel-SRO is a newly developed slow-release formulation of bromocriptine, which prevents initial plasma peak--a known source of adverse events--and extends the half-life of the compound, an interesting feature for the management of motor symptoms in Parkinsonians. This study was designed to determine the best daily administration schedule for 30 mg Parlodel-SRO in 18 parkinsonians previously treated with levodopa and standard Bromocriptine (Br). The 30 mg dose was replaced from one day to the next, in a randomized, double-blind latin square design trial. Three consecutive 7-day courses were implemented, during which a total daily dose of 30 mg P-SRO was administered in one dose, two intakes (b.i.d.) and three intakes, (t.i.d.) respectively. The b.i.d. schedule produced the best improvement in UPDRS scores, especially as to postural stability, walking, bradykinesia; it also provided greater pharmacological stability throughout the assessment day. Adverse event analysis was not in favor of a single daily dose. It appeared that P-SRO administered in two 15 mg intakes (morning and evening) produces the best benefit-risk ratio in Parkinsonians who were already being treated with levodopa.