Broncho-Vaxom (B-V) is a lysate of eight bacterial pathogens of the respiratory tract with immunomodulatory properties. It is used in prophylaxis of respiratory tract infections. We conducted an open, placebo controlled, cross-over trial of B-V treatment in patients with common variable immunodeficiency (CVID). B-V or placebo were given for the period of four months either in winter or spring period. No significant improvement of clinical state of patients during the period of B-V treatment compared with the period when placebo was administered was observed. When subjective comparison of the health state of patients with the same period of the previous year was assessed, significant improvement after B-V treatment compared to placebo was recorded. Evaluating serum immunoglobulin levels a significant increase in serum IgA level was observed after B-V treatment. The results warrant further studies of B-V treatment in CVID patients.