A clinically euthyroid woman had substernal goiter and thrombocytopenia. There was a striking elevation in serum thyroxine (T4) level when the level of triiodothyronine (T3) ws low, reverse T3 (rT3) was normal I131 uptake was suppressed, and thyroid stimulating hormone (TSH) response to thyrotropin-releasing hormone (TRH) was blunted. The elevation of T4 was transient and required no treatment. Postmortem examination revealed a thyroid gland that showed only multinodular goiter. Multiple factors contributed to the dissociation between T4 and T3 levels. There was a lack of clinical symptoms in the face of high T4 and normal T3. The report stresses the need for thorough evaluation of thyroid function in such cases before instituting treatment.