In 1969-70, the research department of the Children's Television Workshop (CTW) established research sites in day care centers to provide feedback to the CTW staff and to conduct a controlled study of the educational benefits derived from viewing the program "Sesame Street." A randomized sample of 200 preschool students was given an extensive battery of pretests and then divided into subsamples of viewers and nonviewers. After the first three months of viewing in the fall of 1969, the students were retested. The results consistently favored the students who had been watching "Sesame Street." The appendixes of this report provide a detailed summary of the pre- and posttest results, including subsamples according to sex, ethnicity, and age. (EMH)