This study investigated the relationship of kindergarten entrance age to academic achievement at the end of grades one through five, and the influence of gender, race, and family income on student achievement. A total of 185 students who attended a Cooperative Demonstrative Kindergarten during 1979-82 and remained in the Starkville (Mississippi) public school system for 6 consecutive years served as subjects. Younger students were defined as those who entered kindergarten at 5 to 5.5 years of age; older students were 5.6 years and older at entrance. Analyses were made on: (1) California Achievement Test Scaled Scores and total reading and mathematics scores for grades one through three; and (2) Stanford Achievement Test Scaled Scores and total reading and mathematics scores for grades four and five. Findings indicated no significant age differences between mean achievement scores in reading and math at the end of first, second, third, fourth, and fifth grades. Older entrants achieved higher mean scores in reading and math in grades one through three. Younger entrants caught up with or passed older entrants in reading and mathematics in grades four and five. When variables of gender, race, and family income were considered, the two age groups did not differ in achievement. However, a significant difference for gender in reading at the fifth grade level favored older females. (RH)