Objective To investigate the incidence of urolithiasis in the children who ingested milk powder tainted with melamine in the Chengdu area. Methods A total of 5 795 infants were screened for urolithiasis by ultrasound examination from September 17, 2008 to December 9, 2008. The data were analyzed using SPSS 13.0 software.Results Twenty-four children were diagnosed with urolithiasis with an incidence of 0.41%, including 12 males and 12 females. The mean age of those children with urolithiasis was 2.35±1.68 years old. No significant difference was shown in the incidence of urolithiasis between males and females (Pgt;0.05). The incidence of urolithiasis in the infants aged 0-3 was significantly higher than that in the children who were more than 3 years old (Plt;0.05). Conclusion The incidence of urolithiasis in the infants aged 0-3 in Chengdu and the surrounding areas is relatively high. Further data should be collected during the follow-up of these cases.