In an open, non-comparative clinical phase IV multicentre study the efficacy and safety of the GnRH agonist leuprorelin acetate depot (LAD) for patients with at least one symptomatic uterine leiomyoma was assessed. 144 premenopausal patients were enrolled and treated with up to six injections of 3.75 mg LAD/month subcutaneously prior to surgical intervention, e.g. either hysterectomy or myoma enucleation. Due to a profound suppression of serum-estradiol levels to castration range (< or = 30 pg/ml) an average volume reduction of all myomas from 86.6 +/- 101.3 ml to 38.5 +/- 63.5 ml became obvious for 90% of all patients. In parallel a significant shrinkage of uterine volume was observed. At baseline 43 patients were planned to undergo a hysterectomy. 29 of these 43 patients could be switched after therapy with LAD to an enucleation as appropriate surgical treatment. In addition a number of patients with scheduled myoma enucleations which were planned to be performed via laparotomy could definitely be operated laparoscopically. Treatment was generally well tolerated. Most of the observed side effects were related to hypoestrogenism. The results of this study have shown that medical pretreatment for patients with uterine fibroids with LAD prior to surgical intervention is an effective measure to improve operability and could lead for several patients to minimal invasive surgery.