Thyrotoxicosis can present with a wide array of clinical manifestations, among which pancytopenia is a rare entity. The disease itself, as well the treatment, can result in pancytopenia which makes the diagnosis more difficult and crucial. The mechanisms underlying are poorly understood currently. Antithyroid drugs which are well known to produce cytopenias as a side effect can safely be implemented in the management. Pancytopenia of thyrotoxicosis should completely reverse with the establishment of euthyroid state. We report a rare case of thyrotoxicosis presenting with pancytopenia which completely resolved with antithyroid treatment.