We report a case of hydralazine-induced alveolar hemorrhage and anti-neutrophil cytoplasmic antibody (ANCA)-positive pauci-immune glomerulonephritis, with serum anti-histone antibodies present, features not previously described in the literature with this drug. A 50-year-old Caucasian female had hypertension treated with hydralazine 75mg TID for three years, and a lung nodule followed up periodically with chest-computed tomographies. She was admitted to the hospital for hemoptysis and newly discovered diffuse pulmonary ground-glass opacities. Transbronchial lung biopsy showed alveolar hemorrhage. Serum creatinine was 3.5 mg/dL and urinalysis showed 2+blood, 30-50RBC/hpf and red blood cell casts. ANCA against myeloperoxidase were present. Anti-double-stranded DNA, ANA, and anti-histone antibodies were positive. Serum complements were normal. Renal biopsy revealed focal crescentic necrotizing glomerulonephritis with negative immunofluorescence, consistent with pauci-immune ANCA-positive vasculitis. Serum creatinine returned to baseline three days after hydralazine was discontinued, and the hemoptysis resolved after treatment with cyclophosphamide and prednisone was started. We concluded that this case represents a hydralazine-induced small vessel vasculitis rather than an idiopathic one. The possibility of hydralazine-induced vasculitis should be considered when patients treated with hydralazine develop a pulmonary-renal syndrome. Anti-histone antibodies may be present in the absence of full classification criteria of drug-induced lupus.