The impact of student teachers upon the attitude and achievement of high school students was studied from 1962 to 1966 to determine the adequacy of student teachers. An experimental group was composed of a representative sample of students (grades 10-12) and graduates who attended the University of Nebraska's University High School and were taught entirely by supervised student teachers. A control group was composed of students and graduates from Nebraska high schools staffed by regular teachers. An attitude scale was created to measure the affective domain, and scores on the National Merit Scholarship Qualifying Test (NMSQT) along with university grade point averages were used as measures of high school and post high school cognitive achievement. Analysis of covariance was used in making the comparison, with intelligence quotient and socioeconomic level being the covariants. Results indicated that students taught by student teachers reached a higher level of achievement than did students taught by regular teachers. Therefore, instruction provided by supervised student teachers seemed to be no less effective than that provided by experienced teachers. Also, the impact of student teachers upon student attitude toward school and teachers was as positive as that of regular teachers and is greatest and most positive in close student-teacher contact. (Included are a list of 34 tables and five appendixes). (Author/SM)