Two experiments investigating the efficiency of communication between 5th grade children from differing socioeconomic (SES) backgrounds are described. In each experiment, 40 same-sex pairs, half male and half female, were formed into dyadic groupings by combining lower- and middle-SES children into the four possible speaker-listener combinations. The task required one child to locate a toy car in a model city from the verbal description of another child. Task success depended on the efficiency of verbal communication of the pair. The listener was allowed to give feedback in the second experiment only. SES combination main effects were observed only for the number of errors made in Experiment 1, with the lower-SES-speaker, middle-SES-listener dyad making the most errors. Sex main effects showed general superiority of the girls in the no-feedback experiment. Content analyses of speaker and listener messages revealed several sex by SES interactions in Experiment 2. Results indicate that a complex, concrete task of this kind elicits similar levels of communication efficiency in children of varying social background but suggest that different communication strategies may be employed toward the same end. (Author/BF)