PXMPI-L (synonyms: PMP69, P70R) is a peroxisomal protein that belongs to the ABC-transporter superfamily. Its closest homolog is the peroxisomal membrane protein 1 (PMP70). We have cloned the mouse PXMP1-L gene. It encodes a 606 amino acid protein. In contrast to the human and the rat, mouse PXMP1-L is predominantly expressed in the liver. The mouse PXMP1-L gene consists of 19 exons and spans 21 kb of genomic sequence. No obvious peroxisome proliferator response element has been found in 1.1 kb of the putative promoter region. No coordination of constitutive or fenofibrate-induced expression of PXMP1-L with other peroxisomal ABC transporters was observed so that an obligate exclusive heterodimer formation is not likely to occur. The data presented will be particularly useful for the generation of a mouse model defective in PXMP1-L in order to elucidate the yet unknown function of this protein.