Cells prepared from the mucosal layer obtained from the fimbrial, proximal ampullary and distal ampullary regions of the human uterine (Fallopian) tube have been grown in monolayer culture, Immunocytochemistry with anti-cytokeratin, anti-vimentin or anti-CD 45 antibodies indicated that the overwhelming number of cells were epithelial in nature and were free of fibroblasts and leukocytes, Basal and steroid-stimulated placental protein 14 (PP14) production was investigated in tissue obtained from nine patients undergoing hysterectomy, by addition of oestradiol and/or progesterone to confluent cultures, Basal PP14 production varied considerably between experiments, probably due to differences between individuals from whom the tissue had been obtained, However, there was no difference in basal PP14 production by cells prepared from the fimbrial, proximal ampullary and distal ampullary parts of the tube obtained from the same patient, When total PP14 production by cells obtained from an individual uterine tube was pooled both progesterone and oestradiol significantly (P < 0.05) stimulated the production of PP14 but the effect of progesterone either alone or in the presence of oestradiol was numerically greater than that of oestradiol alone, Considering PP14 production by cells prepared from the different regions of the tube showed that cells from the fimbrial region were more responsive to steroid stimulation than cells prepared from either the proximal or the distal ampullary regions, All combinations of hormonal supplementation stimulated PP14 production by cells from the fimbrial region on all days measured (P < 0.05 - P < 0.001), In contrast oestradiol alone had no effect on PP14 production by cells prepared from the proximal and distal ampullary parts of the tube on any day measured, Maximum oestradiol-stimulated PP14 values, expressed as percentages of control, were (mean +/- SEM) 146 +/- 11, 113 +/- 7.5 and 108 +/- 8.5 for cells prepared from the fimbrial, proximal ampullary and distal ampullary portions of the tube respectively, Maximum progesterone or progesterone plus oestradiol-stimulated values were very similar; those for progesterone plus oestradiol were (mean +/- SEM) 151 +/- 8.6, 130 +/- 6.2 and 118 +/- 10 for cells from the fimbrial, proximal ampullary and distal ampullary parts of the tube, The results show that a cell culture system has been established which allows the investigation of the function of human uterine tubal cells in culture, Using this system we have shown that PP14 production by these cells is stimulated by steroids and that cells prepared from the fimbrial region of the uterine tube appear more responsive to steroid stimulation than those prepared from other regions of the tube.