Effective induction of the specific mucosal immunity against the outer membrane protein P6 of Haemophilus influenzae was investigated. Twenty-four BALB/c mice were intranasally immunized with P6, twice, with 2 weeks in between, with or without intranasal cytokine treatment. The intranasal immunization evoked both anti-P6 specific mucosal IgA immunity and systemic IgG immunity. In addition, intranasal administration of rIL-2 and rIL-5 enhanced anti-P6 specific immune response was maintained for 3 weeks after the final immunization with the intranasal cytokine treatment. These suggest the possibility of intranasal immunization and the advantage of intranasal administration of cytokines for eliciting both mucosal and systemic immunity.