We have cloned a Drosophila homolog of the membrane fusion protein CDC48/p97. The open reading frame of the Drosophila homolog encodes an 801 amino acid long protein (TER94), which shows high similarity to the known CDC48/p97 sequences. The chromosomal position of TER94 is 46 C/D. TER94 is expressed in embryo, in pupae and in imago, but is suppressed in larva. In the imago, the immunoreactivity was exclusively present in the head and in the gonads of both sexes. In the head the most striking staining was observed in the entire neuropil of the mushroom body and in the antennal glomeruli. Besides TER94, sex-specific forms were also detected in the gonads of the imago: p47 in the ovaries and p98 in the testis. TER94/p47 staining was observed in the nurse cells and often in the oöcytes, while TER94/p98 staining was present in the sperm bundles. On the basis of its distribution we suggest that TER94 functions in the protein transport utilizing endoplasmic reticulum and Golgi derived vesicles.