Objective: Pulmonary aspergillosis is a serious opportunistic infection which might be fatal in immunocompromised patients. Immunity against aspergillosis requires the coordinated action of components of the innate and adaptive immune systems. Beta-glucan is one of the immunomodulatory agents which got much attention in recent years. It was used as a preventive agent for the development of infections. However, information about its the possible protective effect on fungal infections are limited. The aim of this study aimed to investigate the possible protective effects of beta-glucan against Aspergillus fumigatus infection. Material and Methods: We evaluated oral beta glucan administration for its ability to enhance resistance of the rats to experimentally induced pulmonary aspergillosis. Fifty-eight rats were divided into three groups: Thirty five rats were immunosuppressed and infected with Aspergillus fumigatus (infected group); 15 were immunosuppressed, infected and treated with oral beta-glucan (beta-glucan group); and eight were healthy controls. Rats were sacrificed on the tenth day of the experiment and tissue specimens were cultured. Chitin, galactomannan antigen and glucan levels were detected. Results: Beta-glucan enhanced the resistance against Aspergillus infection. The survival rates were 62.9% and 93.4% in the infected and beta-glucan groups, respectively (p<0.05). Beta glucan also limited the fungal burden. Conclusion: Our results suggested that Aspergillus invasion did not develop in beta-glucan group in spite of the occurence of fungal colonization in neutropenic rats. Beta-glucan was able to improve the resistance against A. fumigatus infection.