The effectiveness and long-term tolerability of a new formulation of bromocriptine with slow gastrointestinal release (Parlodel SRO) has been evaluated on ten patients with macroprolactinoma, seven patients with microprolactinoma and five patients with nontumoral hyperprolactinemia during a period of 1-30 months. Six out of ten macroprolactinoma-bearing patients obtained a rapid normalization of plasma PRL levels with reduction of the tumor size recorded by CT scan follow-up. Four of six microprolactinomas and all the five nontumoral hyperprolactinemic patients became normoprolactinemic with recovery of gonadal functions while in two other microprolactinomas Parlodel SRO significantly reduced plasma PRL levels with restoration of menses. Only in two patients the treatment was withdrawn for the appearance of side effects. In conclusion, Parlodel SRO is an effective drug in the management of tumoral and nontumoral hyperprolactinemia. The good long-term tolerability together with the hypoprolactinemic activity makes this drug a very good choice therapy in hyperprolactinemic syndromes even in case of poor tolerability to the standard formulation of the drug.