Intratracheal inoculation of 2 Belgian H3N2‐influenza viral strains, isolated from sick swine in the field, caused high fever, anorexia and dyspnoe in unvaccinated swine. The strains are related to the human A/Port Chalmers/ 1/73 (H3N2)‐strain. In a limited study, 2 subunit vaccines, both derived from the human A/Philippines/2/82 (H3N2)‐strain, were tested for efficacy in protecting swine against these Belgian field isolates. Vaccine A was a commercial vaccine, vaccine B an experimental vaccine. For evaluation of the efficacy of the vaccines, clinical as well as virological parameters were used. It was found that 2 spaced injections of the experimental vaccine (B) resulted in very high serum hemagglutination‐inhibition (HI) titres against the Philippines‐strain. Nevertheless, only partial protection was obtained, as indicated by the milder clinical signs and the decreased viral replication at challenge. One injection of the experimental vaccine (B) and 2 spaced injections of the commercial vaccine (A) dit not result in any protection at challenge, even though moderate HI titres against the Philippines‐strain were obtained. It was concluded that if an H3N2‐strain is included in vaccines for use in swine, a strain should be selected which is identical or very closely related to the strain(s) prevalent in the swine population of the country in which the vaccine will be used.