The effect of month of birth on skill development in language, reading, and mathematics was examined separately for kindergarten and first grade children. The study looked at the strength of the relationship at the beginning and end of the school year and as a function of the type of program in which the child was enrolled. One hundred and thirty-nine kindergarten children and 79 first graders participated in the study. Approximately half of the kindergarten children (N=69) were enrolled in a half-day traditional program while the others were enrolled in a full-day academic-oriented program. Measures administered at the beginning of the year included a language and mathematics test from the CIRCUS series and the Auditory Test from the Metropolitan Readiness Test. At the end of the school year, all the subjects were given the Reading, Language and Mathematics Tests from the Metropolitan Achievement Test. Results indicated a small but statistically significant relationship between month of birth and skill level at the beginning of kindergarten. At the end of the year, only the performance on the mathematics test was correlated to age for the kindergarten children and there was no relationship for first graders. Type of program did not alter the pattern of results. (Author/MP)