Benzoate X receptor (BXR) is a member of the nuclear hormone receptor superfamily and is activated by alkyl esters of amino benzoic acids and expressed during early development stages. We report here a second BXR, which was cloned by screening Xenopus laevis embryonic cDNA libraries. This new BXR, termed BXR beta, exhibits 97% identity in the DNA-binding domain and 79% identity in the ligand-binding domain in amino acid sequence to previously reported Xenopus BXR. The BXR beta strongly binds as a heterodimer with retinoid X receptor (RXR) to direct repeats of an AGGTCA motif spaced 4 or 5 base pairs apart and activates transcription by addition of methyprednisolone and dexamethasone as well as amino- and hydroxybenzoates.