Objective To investigate the efficiency of meropenem in treating secondary peritonitis in newborn infant. Methods Twenty-four newborn infants with secondary peritonitis were treated by meropenem from January 2006 to June 2009 in Tianjin Childrens Hospital. The therapeutic effects were evaluated in the 24 cases. Results Twenty-one patients revealed positive of germiculture and 30 germ strains were isolated from the culture. After the treatment with meropenem, complete cure were observed in 21 newborns. One case gave up treatment,and the other two died. Overall bacterial clearance rate was 86. 7%. Both the clinical cure rate and the total cure rate were 87.5%. The clinical effect consisted with bacteriological effect. Conclusions Meropenem is effective and safe in the treatment of secondary peritonitis in newborn infant.