This study investigated selected sixty fifth grade students of a public elementary school how the verbal interaction in cooperative small groups affect their analogical reasoning for solving mathematics and nature science isomorphic problems. Children who had been engaged in the cooperative instruction condition performed significantly better than those in the conventional instruction condition on solving mathematics problems rather than solving nature science problems. Children who participated in the cooperative instruction condition exhibited more comprehension questions and answers, and low level explanation than those who in conventional instruction condition did. No significant differences between conditions, in critical and connection questions and answers. It´ important for instructors to encourage children to use vocabulary and elaboration explanations with peers in small groups as well as to activate their learned knowledge in analogical problem solving.