The Paired School Science Project (PSSP) conducted between public and parochial schools was evaluated over a period from 1968-71. A pilot program was carried out among fifth and sixth grade students of 30 schools in the 1967-68 school year. During the study period, these classes of the paired schools were bused to the Franklin Institute for integrated physical-biological science instruction one day a week for seven weeks. Students ate lunch together and then left for their respective schools. The program was extended to a whole day experience beginning in 1970, and a workshop for teachers and principals was added during the last school year. Museum resources and examination of urban environmental problems were emphasized. The student interaction category system, cultural awareness questionnaires, achievement tests, semantic differentials, sociometric studies, and interview techniques were used in evaluation. A parent questionnaire was used in the 1970-71 school year. Analyses showed that significant gain differences existed between the PSSP and the control groups. Parent participation was fairly successful. Sensitivity to environmental problems was enhanced, and student interactions occurred mostly between paired schools from similar geographic locations. Six days of social interaction had little effect on student attitude changes. (CC)