The antibody response against Asian influenza virus was measured in 619 volunteer subjects who received Asian influenza vaccine or polyvalent vaccine in varying dosage at various time periods by the subcutaneous or intradermal routes. Blood was taken from each subject before and after the vaccination and was titrated for hemagglutinationinhibiting (HI) antibody. Pure egg-line Asian influenza virus strain A/Japan/305/57 in the fifth passage in eggs was used in these tests. When this strain of virus was used it was unnecessary to treat the serum with receptor-destroying enzyme or with potassium periodate. The vaccination was followed by marked rise in HI titer even when as little as 62.5 CCA units of virus were given. Some benefit from the second dose of vaccine was also demonstrated. Persons who received 200 CCA units developed as much antibody as did persons with proved cases of the disease. Reactions to the vaccine occurred in 18 subjects but were generally mild and inconsequential.