The Comprehensive School Mathematics Program (CSMP) is a program of CEMREL, Inc., one of the national educational laboratories, and was funded by the National Institute of Education (NIE). Its major purpose is the development of curriculum materials for grades kindergarten through 6. This is a report of the first year of a 2-year evaluation of the CSMP fifth-grade materials. The study was intended as both a pilot test of certain scales and a preliminary comparative evaluation of CSMP/non-CSMP achievement. A small group of St. Louis area classes were chosen for the pilot study. Main results noted: 1) Significant differences in favor of CSMP classes in mental arithmetic, number relations, number systems (other than whole numbers), certain word problems, and problems with multiple correct answers; 2) no significant differences on standard computation, geometry, probability, and place value; 3) similar results for comparisons of the two groups by sex and at different levels of reading ability; 4) a consistency with previous findings, particularly those in large-scale fourth-grade comparisons. (MP)