The cytogenetic patterns of uterine leiomyomas have been extensively investigated, and cases characterized by specific clonal changes have been documented in detail. In these tumors one of the cytogenetic changes frequently observed has been a del(7), particularly del(7)(q22), usually as a sole anomaly. This is confirmed by our experience and by reports in the literature. The fact that del(7) is one of the most common abnormalities in leiomyoma raises the question of its role in tumor development. The main purpose of this review is to analyze the above aspect and to interpret its possible meaning. Our findings on cytogenetic abnormalities of chromosome 7 in leiomyoma, together with those reported in the literature, are reviewed and discussed. A listing of the genes located at 7q22 is also presented.