A 26-year-old woman with common variable immunodeficiency syndrome (CVID) associated with frequent episodes of pneumonia underwent an open lung biopsy showing bronchiolitis obliterans organizing pneumonia (BOOP). Following corticosteroid therapy, there were no further episodes of pneumonia. In addition, there was roentgenographic and gas exchange improvement. This is the first case of BOOP in association with CVID. An immunologic basis of BOOP is postulated.