Growth-regulated oncogene α (GROα), a potent chemoattractant for neutrophils, has previously been detected in the endometrial stromal cells (ESC) of human endometrium. In this study, the mRNA expression of GROα in the endometrium was evaluated by reverse transcription–polymerase chain reaction analysis, while the localization of GROα protein was studied by immunohistochemistry and the concentrations of GROα were measured using an enzyme-linked immunosorbent assay (ELISA). The effects of known modulators of endometrial function on the production of GROα by ESC were also examined by ELISA and Northern blot analysis. The expression of both GROα mRNA and GROα protein was detected in the cycling endometrium. GROα protein was localized mainly in the stroma, and endometrial tissues in the secretory phase contained higher amounts of GROα protein than did those in the proliferative phase. The production of GROα by ESC was enhanced by in-vitro decidualization. Lipopolysaccharide, tumour necrosis factor-α and interleukin-1β also stimulated the expression of GROα mRNA and protein by ESC. These results suggest that the production of GROα by ESC is regulated by ovarian steroid hormones as well as by inflammatory mediators. The modulation of GROα concentrations in the local environment may contribute to normal and pathological processes in the uterus by regulating leukocyte trafficking in the endometrium.