Male chlamydial infections are becoming more recognised as an aetiological agent in infertility. An IFN-? response is required for protection against Chlamydia in females, but may have the potential to induce pathology in the immune-privileged male reproductive tract. We examined the induction of immunity following intranasal immunisation with major outer membrane protein (MOMP) of Chlamydia muridarum in male BALB/c mice, and the role of MOMP-specific CD4+ T cells in clearance of an intrapenile infection. Here we report that adoptive transfer of MOMP-specific CD4+ T cells into naﶥ mice confers partial protective immunity, which significantly reduces the tissue burden of Chlamydia.