Compiled primarily from prison administrations for 205 countries worldwide, this report provides detailed information of the number of prisoners held in these 205 independent countries and dependent territories between late 1999 and November 2003. The report describes the differences in the level of imprisonment across the world. Report highlights include: (1) over 9 million individuals were held in correctional institutions throughout the world, mostly pretrial detainees or having been convicted and sentenced with about half of these in the United States; (2) the United States had the highest prison population in the world, some 701 per 100,000 of the national population; (3) more than three-fifths of countries had rates below 150 per 100,000; (4) prison population rates varied considerably between different regions of the world, and between different parts of the same continent; and (5) prison populations were growing in many parts of the world with many previous reports showing that prison populations had risen in 71 percent of these countries. Limitations and weaknesses of the report are presented and discussed. The report is viewed as useful for academic criminologists studying the use of imprisonment worldwide and by non-governmental organizations who are interested in variations in criminal justice practice. Tables