Immunomodulatory activities of crude beta-glucans extracted from oat bran under different conditions, fractions A (55℃,,5%,,pH,6), B (45℃,,15%,,pH,6), C (50℃,,20%,,pH,7), D (50℃,,0%,,pH,7), and E (50℃,,10%,,pH,9) were investigated. All crude beta-glucan fractions stimulated macrophages, producing nitric oxide dose-dependently, and, efficiently promoted nitric oxide production in presence of IFN-gamma. Except for fraction C, in vivo test indicated fractions B, D, and E (100 mg/kg) substantially enhanced carbon-phagocytic indices of blood macrophages by oral administration of crude betaglucan for 7 days prior to carbon injection. These immunomodulatory effects could be determined with extraction conditions of crude beta-glucan.