OBJECTIVE: To report a case of trovafloxacin-associated leukopenia, which occurred in a trauma patient shortly after administration and resolved following discontinuation of the drug. CASE SUMMARY: A 79-year-old white man was admitted to Yale New Haven Hospital after sustaining partial amputation of his right lower leg by an industrial lawn mower. After successful resuscitation, he underwent complete right lower amputation and was treated with intravenous alatrofloxacin mesylate. He developed leukopenia that resolved after discontinuation of the drug. DISCUSSION: Trovafloxacin is a broad-spectrum synthetic fluoroquinolone used for a wide variety of bacterial infections. We report, for the first time in the English-language literature, a case of trovafloxacin-associated leukopenia. The leukopenia resolved promptly after discontinuation of the drug. This association is further supported by the exclusion of other potential causes for this adverse effect. CONCLUSIONS: Leukopenia is a well-recognized adverse effect of several drugs. We report a case of trovafloxacin-associated leukopenia during treatment of a trauma patient. Healthcare personnel should be aware of this possible adverse reaction in patients treated with trovafloxacin.