This survey of 204 regular classroom teachers sought to determine to what extent 65 competencies (identified as essential for special education teachers of the severely handicapped) are necessary for teachers who have special education students mainstreamed into their classrooms. The mainstream teacher sample in this study and a special education teacher sample from a 1987 study both valued the 65 core competencies similarly. Competencies perceived by mainstream teachers as important were also perceived to be possessed to some degree. Thirty-two competencies were rated as important enough to suggest placement within a preservice teacher education program. The strong correlation between inservice special educator ratings and inservice mainstream teacher ratings on the importance of the core competencies suggests a shared "subcore" of competencies which has the potential for bringing the mainstream teacher and the special educator together for collaboration. Preservice and inservice program implications are listed. (JDD)