Objective: To evaluate clinical features and laboratory tests of acute renal failure (ARF) in paraquat poisoned patients. Subject and method: The observational study involved in 68 patients with acute paraquat poisoning, admitted in Poison Control Center, Bach Mai Hospital from 2011 to 2012. Result: Overall mortality rate was 64.7 percent, similar between female and male. The most common reason of poisoning was suicidal (88.2 percent). Multiple organ failure was valuable indicators of poor prognosis. The ingestion of a small amount of paraquat solution and early emergency managements were two most important factors for survival. Conclusion: ARF occurred in 77.94 percent of paraquat poisoning patients, about 1.69 days after paraquat ingestion but sooner in severe poisoning cases (lst day, 56.6 percent). The most severe renal impairment happened in 2.97 days after poisoning. Although ARF was severe but serum potassium concentration were usually low (60.38 percent) on admittion and 47.17 percent when the renal failure was at the bottom. The mortality rate in ARF patients is 81.3 percent.