The effect of goal versus goal and task interdependence was compared on achievement, cooperative attitudes, and personal and academic support among cooperative learning groups. Eighty-seven third, fourth and fifth grade Italian elementary school students were involved in a one year cooperative learning program. At the end of the year students were assigned to experimental conditions and participated in three consecutive instructional sessions of 90 minutes each. Achievement, cooperative attitudes, and perceptions of social support were individually assessed at the end of the third instructional session. Students completed the cooperation and social support scales from the Classroom Life Measure. Results on achievement indicated that students assigned to positive goal and task interdependence outperformed students assigned to positive goal interdependence only condition. Students in the goal and task interdependence condition had more positive attitudes toward cooperation and perceived more peer academic support than did students assigned to the goal interdependence only condition.