OBJECTIVE: To examine the expression of PDGF and its receptors in leiomyoma tissue and to investigate the regulation of PDGF on leiomyoma cell proliferation. MATERIALS AND METHODS: The expression of PDGF and its receptors was examined in 21 pairs of uterine leiomyoma and the adjacent myometrium tissues using an immunostaining method. Paired cultures of leiomyoma and normal myometrium cells were established and treated with PDGF. Total RNA was extracted from leiomyoma and myometrial cells for detection of the expression of proliferating cell nuclear antigen (PCNA) and collagen alpha1 (I, III) by semi-quantitative PCR. RESULT: The expression of PDGF-AA and PDGF-BB in leiomyoma tissue is obviously higher than that in the matched myometrial tissue (P < 0.05). In addition, the expression of PDGF-BB in secretory phase is higher than that in proliferative phase of the menstrual cycle (P = 0.027) in leiomyoma tissue. The expression of PCNA and collagen alpha1 (I) were increased in both leiomyoma and myometrial cells after treatment of PDGF, whereas the expression levels were greater in leiomyoma cells than that in myometrial cells. CONCLUSION: The expression of PDGF and its receptors in leiomyoma and myometrial tissue varied during the menstrual cycle. PDGF may play a role in the pathogenesis of leiomyomas through a mechanism involved in not only the proliferation of leiomyoma cells but also excessive expression of extra cellular molecules.