Objective: Recent studies have demonstrated the therapeutic effects of bone marrow–derived cells in tissue regeneration. The aim of this study was to investigate the effects of bone marrow mononuclear cell (BMMC) transplantation in a mouse model of acute renal failure (ARF) induced by mercuric chloride. Methods: BMMC was isolated from male BALB/c mice and injected into female mice treated with a lethal dose (LD90) of mercuric chloride. Survival rate, histopathological analysis, and assessment of urea, creatinine, sodium, potassium, and mercury levels were carried out. Results: Cellular therapy with BMMC significantly reduced the mortality induced by mercuric chloride (p < 0.05). This finding correlated with a decrease in serum levels of urea (p = 0.04) and potassium (p < 0.01). However, no differences in renal morphology were observed when BMMC-treated and control group were compared. Conclusion: Transplanted BMMC improve renal function and reduce mortality and, therefore, may represent a new therapeutic alternative to treat ARF.