Reported is a study to compare science achievement of 318 ninth-grade students who came from different socioeconomic areas but all enrolled in an Earth Science Curriculum Project (ESCP) program. The students were divided into three socioeconomic groups: upper, middle, and lower. All were given a pretest in science achievement, a posttest, an intelligence test, and an attitudinal scale examination. To find a significant difference among the groups, the analysis of covariance was implemented. The science achievement pretest, intelligence test and attitude inventory served as controls to measure science achievement during the school year. The Duncan's Multiple Range Test was applied to each group to find any significant difference between groups. The t-test and multiple correlating were implemented to find relationships between the students' intelligence and attitude and their posttest. The F value derived for the three groups was significant at the .05 level. The Duncan's test revealed a significant difference between upper and middle socioeconomic groups and the upper and lower groups. There were no significant differences between the middle and lower socioeconomic groups. Intelligence was an influencing variable on the students' science achievement. The variable of attitude and science achievement showed no significant relationships. (Author/EB)