A 44-year-old man with nasal and respiratory symptoms combined with positive serum antibodies to neutrophil cytoplasmic antigens (ANCA) suggestive of Wegener's granulomatosis was treated with antibacterial agents. Complete clinical response was achieved with co-trimoxazole, and the titer of ANCA declined. After a 12-month treatment period, the patient contracted fever and respiratory symptoms and fatigue again, and he had proteinuria and hematuria. After the institution of conventional treatment with oral prednisolone and cyclophosphamide, a favorable response was achieved. Wegener's-like granulomatosis is difficult to diagnose at its early stage, but the presence of ANCA may be helpful. We suggest that co-trimoxazole should be considered as a first-line treatment, under careful supervision, for young patients whose disease is limited to the respiratory organ.