While preparing a previous ERS Report, Employee Absenteeism: A Summary of Research, Educational Research Service found relatively few published studies on teacher absenteeism as compared to the immense literature on absenteeism in business and industry. ERS found no nationwide data relating specifically to either teacher or school support staff absenteeism. To help fill this void, ERS, with the assistance of the American Association of School Personnel Administrators, conducted the first ever national survey on teacher and support staff absenteeism, collecting data for the school year 1978-79. This report provides data on teacher absenteeism; a companion report covers support staff absenteeism. A total of 470 school systems with enrollments of 300 or more students responded to the survey on teacher absenteeism. Data is reported in 41 tables, including teacher absence data, costs of teacher absences and substitute teacher replacement, and attendance policies and procedures. A major portion of the report is devoted to 55 examples in 26 states of how school systems responded to teacher absenteeism at the local level.