Infants in some areas of China developed urinary lithiasis after being fed with powdered milk that was tainted with melamine in 2008 and very small proportion of the infants developed acute renal failure caused by urinary tract calculus obstruction. The aim of this article was to summarize clinical characteristics, diagnosis and treatment of infants with urinary calculus and acute renal failure developed after being fed with melamine tainted formula milk.Data of infant patients with urinary calculus and acute renal failure due to melamine tainted formula milk admitted to the Beijing Children's Hospital Affiliated to the Capital Medical University and the Xuzhou Children's Hospital in 2008 were used to analyze the epidemiological characteristics, clinical manifestations, imaging features as well as effects of 4 types of therapies.All the 34 infants with urinary calculus were complicated with acute renal failure, their blood urea nitrogen (BUN) was (24.1+/-8.2) mmol/L and creatinine (Cr) was (384.2+/-201.2) micromol/L. The chemical analysis on the urinary calculus sampled from 15 of the infants showed that the calculus contained melamine and acidum uricum. The time needed for the four types of therapies for returning Cr to normal was (3.5+/-1.9) days for cystoscopy group, (2.7+/-1.1) days for lithotomy group, (3.8+/-2.3) days for dialysis group, and (2.7+/-1.6) days for medical treatment group, which had no statistically significant difference (P=0.508). Renal failure of all the 34 infants was relieved within 1 to 7 days, averaging (3.00+/-1.78) days.Melamine tainted formula milk may cause urinary calculus and obstructive acute renal failure. It is suggested that firstly the patients with urinary calculus complicated with acute renal failure should be treated with dialysis or medication to correct electrolyte disturbance, in particular hyperkalemia, and then relieve the obstruction with available medical and surgical methods as soon as possible. It was observed that the short-term prognosis was satisfactory.