The in-vitro maturation protocol (IVM) is an intriguing tool in assisted reproduction since it omits the side-effects of drug stimulation and reduces the cost of the entire procedure, both in terms of time and patient/society costs. In the Biogenesi Reproductive Medicine Centre, the IVM technique has been applied for more than 3 years, obtaining successful results in terms of maturation and fertilization rates, number of pregnancies and healthy babies born. At present, IVM is widely accepted in polycystic ovary and polycystic ovarian syndrome patients but its application in other women is still controversial. This study has been carried out in order to determine the efficiency of unstimulated IVM in women with morphologically and endocrinologically normal ovaries. Body mass index, basal FSH and oestradiol concentrations, antral follicle count, endometrial thickness and lead follicle size were correlated with the outcome of the procedure so as to obtain useful criteria to select women with regular cycles for an IVM technique. It was found that basal oestradiol concentration, FSH concentration and antral follicle count are useful criteria in deciding whether to start and continue the procedure, while lead follicle size and endometrial thickness are important criteria in deciding the timing of oocyte retrieval.