Uterine myomas represent one of the most frequently manifested benign tumors in women. They originate from smooth muscle cells of myometrium or its blood vessels. Many studies suggest that inflammation and pro-inflammatory factors may play a role in the carcinogenesis with an involvement of the transcription factor NF-kappaB which activity can be controlled by various environmental factors, including many cytokines. The aim of the study was to investigate the expression of NF-B, interleukin-1β (IL-1β), tumor necrosis factor a (TNF-α), cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS) in myometrium and uterine myomas of women of various age. The expression of NF-kappaB, selected cytokines and enzymes was estimated in women of reproductive or perimenopausal age by semiquantitative immunohistochemistry. The expression of the examined proteins was higher in myomas than in control myometrium and was dependent on the size of myomas and the age of women. However, the expression of the cytoplasmic NF-kappaB observed in uterine myomas was independent on the size of myomas and no significant differences were observed in the number of stained nuclei between control and myoma groups. Thus, the expression of proinflammatory factors in myomas was not accompanied by the nuclear activation of NF-kappaB p65. The results of our study indicate that the examined factors may be involved in the pathogenesis of benign tumors and not only malignant diseases. (Folia Histochemica et Cytobiologica 2013, Vol. 51, No. 1, 73–83)