This is the case of a 41-year-old renal transplant recipient taking tacrolimus immunosuppressive therapy, who had a large pleural effusion, found on a chest radiograph during the work-up of digital clubbing. The patient had undergone a renal transplant 17 months earlier for end-stage renal disease secondary to immunoglobulin A nephropathy. Analysis of the effusion fluid demonstrated a lymphocytic exudate. Biopsy specimens of pleural and lung tissues showed noncaseating granulomas. Fluid and tissue cultures were negative for viral, fungal, and bacterial pathogens. Diagnosis of sarcoidosis was established by identification of noncaseating granulomas in pleural and lung tissue, the exclusion of other conditions, and rapid resolution of the effusion after the institution of corticosteroid therapy. The patient has remained free of pulmonary symptoms and had normal chest radiographs during the 20-month follow-up period.