A 32-year-old woman on maintenance hemodialysis for five years (indeterminate nephropathy, bilateral small kidneys, anuria) presented with recurrent hemoptysis over a six-month period. In a tuberculosis-endemic region, an exhaustive infectious investigation was performed, including repeated sputum and gastric lavage polymerase chain reaction (PCR) and cultures (with 42-day mycobacterial culture), tuberculin skin testing, and bronchoscopy with bronchoalveolar lavage (BAL). BAL revealed abundant hemosiderin-laden macrophages, confirming alveolar hemorrhage. C-reactive protein (CRP) was elevated, but procalcitonin remained normal, arguing against bacterial infection. Echocardiography and abdominal ultrasound showed no abnormalities. Tumor markers were negative. After six months without a diagnosis, an autoimmune panel was obtained: anti-myeloperoxidase antibodies (anti-MPO, P-ANCA) were strongly positive by enzyme-linked immunosorbent assay (ELISA) (>120 IU/mL; normal <20 IU/mL); antinuclear antibodies (ANA) and anti-proteinase 3 antibodies (anti-PR3, C-ANCA) were negative. The patient was treated with prednisone 1 mg/kg/day and monthly intravenous cyclophosphamide 500 mg on non-dialysis days, with complete blood count monitoring. A rapid clinical and biological response occurred, with hemoptysis ceasing within two weeks and radiological resolution at three months. This case highlights that when an extensive infectious workup remains negative in a dialysis patient with hemoptysis, ANCA-associated pulmonary vasculitis should be suspected, especially when CRP is elevated without procalcitonin elevation and BALdemonstrateshemosiderin-ladenmacrophages.