The Mainstream Assistance Team (MAT) Project is a 3-year program to develop, implement, and validate a prereferral intervention model with nonhandicapped difficult-to-teach students. This paper presents a rationale for prereferral assessment and intervention focused on the increasing numbers of mildly handicapped students enrolled in special education, the increasing frequency of teacher referrals for student evaluation, and evidence that teacher referrals may be arbitrary and precipitous. Traditional educational assessment is compared to prereferral assessment and intervention. Then the basic dimensions of the MAT are explained, including behavioral consultation in four stages (problem identification, problem analysis, plan implementation, and problem evaluation) and the use of"written scripts" by consultants to ensure all important information is communicated during formal meetings. During year 1 the project was implemented in four inner-city middle schools with 10 school based consultants. Limited success during the first year led to changes in year 2 including requiring the use of contingency contracts and data based monitoring procedures. During year 3 elementary guidance counselors in 20 schools are being trained in the MAT program. Appended are a sample student-teacher contract; a sample "script"; instructions for teacher and student monitoring with an interval recording system; and instructions for the product inspection approach to teacher and student monitoring. (DB)