This article reports on the short-term impact of a school-based program using older adult volunteers and aimed at improved academic achievement and reduced disruptive classroom behavior in urban elementary school students. The Experience Corps Baltimore (Maryland) program places a critical mass of older adult volunteers, serving 15 hours or more per week, in public schools to perform meaningful and important roles to improve the educational outcomes of children and the health and well-being of the volunteers. This article reports on the preliminary impact of the program on children in grades K-3. A total of 1,194 children in grades K-3 from six urban elementary schools participated in this pilot trial. At follow-up, third grade children whose schools were randomly selected for the program had significantly higher scores on a standardized reading test than children in the control schools, and there was a nonsignificant trend for improvement in alphabet recognition and vocabulary ability among kindergarten children in the program. Office referrals for classroom misbehavior decreased by about half in the Experience Corps schools, but remained the same in the control schools. Teachers had somewhat more favorable attitudes toward senior volunteers as a result of having older volunteers in the classroom, although the difference between the intervention and control schools was not statistically significant. In this pilot trial, the Experience Corps program led to selective improvements in student reading/academic achievement and classroom behavior while not burdening the school staff.