Groups of neonatal mice were immunised with different mucosal vaccines based on acellular (Pertactin antigen) or whole cell (inactivated Bordetella pertussis with Diphtheria and Tetanus toxoid) Pertussis vaccines, using Escherichia coli heat-labile enterotoxin (LT) as a mucosal adjuvant. Neonatal mice tolerated mucosal vaccination well and a significant cellular infiltrate was detected in the lungs of mice receiving mucosal vaccines compared to PBS controls. This infiltrate included B lymphocytes, gammadelta T cells and interferon-gamma producing T cells. Neonatal mice, in contrast to adult mice, responded poorly in terms of the production of serum antibody to Pertussis antigens delivered mucosally, although they were able to mount an anti-Tetanus response to those vaccines harbouring Tetanus toxoid and whole cell Pertussis antigen. Neonatal mice immunised with Pertactin or whole cell Pertussis antigen together with LT were protected against virulent B. pertussis challenge.