The purpose of this study was to compare the reading achievement of third graders who had attended kindergarten for one year with that of third graders who had been given two years of kindergarten. A review of the literature revealed that the majority of studies in this area showed that the practice of retaining students did not serve the intended purpose of increasing the students' academic growth. In the current study, subjects were 142 third graders, 25 of whom had been retained in kindergarten and 117 of whom had been promoted after one year in kindergarten. A standardized reading test was administered. The results of the data analysis indicated no significant difference between the test scores of the retained and promoted students. No positive effects of retaining children in kindergarten on children's later academic achievement were found. It is suggested that developmental maturation, while important, is but one of many factors in a child's ability to learn and profit from school. Implications for educational improvement are provided. A list of 34 references is appended. (GLR)