The sexual phenotype of amphibians is determined either by chromosomal factors (genetic sex determination, GSD), or by environmental factors (environmental sex determination, ESD). Recently, new findings on the sex determination-related genes and their interactions have obtained by utilizing molecular biology methods. Several genes such as DMRT1, DAX1, SF1, SOX3, SOX9, FOXL2, CYP19 and CYP17 have been found to play roles in determining the sexual phenotype of amphibians, with DAX1, SF1, FOXL2 and SOX3 involved in transcriptional regulation of aromatase gene. FOXL2 and SOX3 promote CYP19 expression. DAX1 and SF1 can influence CYP17 expression. Sex-determination genes play their roles by acting on the expression of CYP19 and CYP17. Both sex-determination related genes and temperature determine sex of amphibians by affecting estrogen and/or androgen levels.