A follow-up analysis of data collected in 2003 was conducted to determine the effect of peer helping programs on student achievement at 47 middle schools in Western New York. The mean scores and the percent of students achieving at or above the New York State passing cores on The New York State Eighth Grade Science Achievement Test and The New York State Eighth Grade Math Achievement Test in schools with peer mediation programs were statistically higher for schools with peer mediation programs than without such programs. (Contains 3 tables.)