Conjugation is a complex event directed to ensure the transfer of genetic material, which is achieved by the union of two cells. In fungi, success of this relevant process requires digestion of the cell wall at the point where both cells have agglutinated and, later, the union of the plasma membranes and nuclei from the mating partners. In order to gain information about cell fusion, we have cloned and disrupted the cfr1+ gene from the fission yeast Schizosaccharomyces pombe. cfr1+ gene is slightly induced at the beginning of mating but Cfr1p protein is degraded soon after the cells are transferred to nitrogen-lacking medium. cfr1Delta mutants present a defect in cell fusion owing to a failure in the digestion of the cell walls between the two parental cells. Finally, cytological and genetic analyses show that cfr1+ acts in a new pathway involved in conjugation that is independent of fus1+, the only gene that has been found to be specifically required for cell fusion during mating in the fission yeast.