The San Diego City Schools collected statistics about grades 9-12 students who withdrew from school during the 1979-80 school year. The study's purpose was to determine how many of these former students did not enroll in schools elsewhere and, therefore, should be considered school leavers. The following generalizations may be made from the statistics: (1) the district's school leaver rate was 5.6%; (2) continuation/opportunity schools and special programs had the highest school leaver rates, while regular junior high schools had the lowest rates; (3) for the district, the major specific reasons for school leaving were voluntary withdrawal (over 18), habitual truancy, full-time employment and voluntary withdrawal (under 18); (4) Blacks and Hispanics were overrepresented among school leavers; (5) while few ninth graders were school leavers, the largest number of school leavers left when in Grade 10, but the highest proportion of student losses was experienced by Grade 11; (6) there was little difference between numbers and rates at which male and female students became school leavers during the 1979-80 school year. (PS)