Acyl-CoA synthetase 4(ACSL4) is an arachidonate-preferring enzyme abundant in steroidogenic tissues and postulated to modulate eicosanoid production. The human and mouse ACSL4 gene are mapped on chromosome X. The female mice heterozygous for ACSL4 deficiency became pregnant less frequent1y and produced small litters, with 40% of embryos surviving gestation. In this study, we examined the regulation of ACS4 by estradiol-$17{eta}$ and progesterone (P4) in the human endometrial cancer cell line HTB-1B. ACSL4 mRNA was increased in a dose-dependent manner. Also, expression of ACSL4 gene was up-regulated in a time-dependent manner in HTB-1B cells. However, combined treatment with progesterone and estradiol-$17{eta}$ modestly decreased the levels of ACS4L mRNA as compared with the estradiol-$17{eta}$ and progesterone respectively. Overall, these results suggest that the ACSL4 gene is regulated by progesterone and estradiol-$17{eta}$ in the HTB-1B cells.