This report is the third retention report published by the Massachusetts Department of Education (MADOE) to provide districts and the public general information on student retention in Massachusetts. Retention is defined as repeating a grade--students are retained when they are required to repeat the grade in which they were enrolled in the previous year. For the 2004-05 school year, retained students were reported to be enrolled in the same grade as they were in during the 2003-04 school year. In this report, retention data are reported as both a number and a rate (the number of students retained divided by the enrollment). In the 2004-05 school year, Massachusetts public schools retained 22,834 students out of a total of 882,956 students enrolled in grades 1-12 only, equivalent to a statewide retention rate of 2.6 percent. Students are not retained in kindergarten. The report summarizes various state-level data pertaining to students retained in the 2004-05 school year including analyses by demographics, program areas and MCAS performance. Each section contains a brief summary of the statistics and includes graphs and tables detailing the data where appropriate. In addition, there are two appendices at the end of the report: (1) District Retention Rates by Grade Level; and (2) District Retention Rates by Race/Ethnicity Categories. (Contains 25 tables, 4 figures and 5 footnotes.)