The patient, a 15-year-old boy, presented with a 3-month history of nausea, vomiting, fatigue, and worsening headache. Results of physical examination were notable for enlargement of occipital, cervical, axillary, and inguinal lymph nodes, mild hypertension, and scattered hypopigmented plaques over the posterior neck and extensor surfaces of multiple joints. Initial laboratory tests revealed the following values: serum creatinine 2.2 mg/dl, serum calcium 12.9 mg/dl, and ionized calcium 1.74 mmoles/liter. Abdominal ultrasound demonstrated retroperitoneal lymphadenopathy and medullary nephrocalcinosis. Radiographs of the chest (A) showed a subtle interstitial prominence, without evidence of hilar adenopathy. Diffuse miliary interstitial nodules throughout the lung parenchyma were seen on computed tomography of the chest (B). Results of pulmonary function tests were within normal limits. Additional laboratory studies showed undetectable levels of parathyroid hormone (PTH) (<3 pg/ml) and PTH-related peptide (<2 pmoles/liter), low 25-hydroxyvitamin D levels (18 ng/ml), and elevated serum lysozyme levels (28 μg/ml). Levels of angiotensin-converting enzyme and 1,25-hydroxyvitamin D were within normal limits. The patient underwent transbronchial lung biopsy (C) and lymph node biopsy (D), which revealed multiple noncaseating epithelioid granulomas (arrows) and prominent areas of hyalinization (arrowheads). No evidence of mycobacterial or fungal infections was found on serologic tests, histologic stains, or tissue culture. Sarcoidosis was diagnosed, and initiation of corticosteroid therapy resulted in rapid resolution of hypercalcemia and improvement of the serum creatinine level within 1 week. Complete resolution of lymphadenopathy was seen after 4 months. To our knowledge, this is the first description of miliary sarcoidosis in a pediatric patient.