This article provides a quantitative review of the type, number, and estimated weight of the fish stocked by the 50 state agencies and the U.S. Fish and Wildlife Service in the United States in 2004. I examined trends in the light of data from earlier reports dating back to 1931. Among other things, this analysis shows that 1.7 billion fish were stocked by these agencies in 2004, representing 104 types of fish weighing an estimated 19.8 million kg. This was the largest number of types of fish (species, subspecies, and hybrids) and the largest total weight of fish ever stocked for those years for which information was available. Because many fish are being stocked at larger sizes, the total number of fish stocked in 2004 was in fact lower than in the first half of the twentieth century. Reflecting a long-term trend, most of the stocking was done by state agencies. The majority of the fish stocked (by estimated weight) were in western states and the most commonly stocked fish by this measure were coldwater sportfish, especially rainbow trout (Oncorhynchus mykiss).