Pulmonary alveolar microlithiasis is an uncommon infiltrative pulmonary disease characterized by deposition of microliths in the alveoli. We present the case of a young adult with complaints of shortness of breath on exertion. Chest radiograph showed innumerable small, dense nodules, diffusely involving both the lungs - predominantly in the lower zones. High-resolution CT scan illustrated widespread intra-alveolar microliths, diffuse ground-glass attenuation areas, septal thickening, and black pleural lines - predominantly in the basal regions. Transbronchial biopsy confirmed the diagnosis.