Adult T-cell leukemia/lymphoma (ATLL) is a rare and often aggressive T-cell leukemia/lymphoma that has been linked to infection by the human T-cell lymphotropic virus type 1 (HTLV-1). ATLL can involve multiple organs including the respiratory airway. A 53-year-old Trinidadian woman presented with productive cough and progressive shortness of breath. Her past medical history included duodenal strongyloidosis, skin rash, and hypercalcemia. Radiological studies showed increased interstitial markings. Sputum cytology showed atypical pleomorphic, small-to-medium-sized, lobated lymphocytes with irregular and hyperchromatic nuclei resembling "flower cells" which were CD3±/CD20- by immunocytochemistry. A lung biopsy showed interstitial, peribronchiolar, and subpleural infiltration by a CD3±/CD25± atypical lymphocytic infiltrate. Together with peripheral blood findings and positive HTLV-1 serology, the diagnosis of ATLL was made. We suggest that sputum evaluation in patients with ATLL risk factors can be diagnostic.