A catalog of the American species of Dolichopodidae north of Mexico is provided. Fifty-five valid genera and 1288 valid species and 3 subspecies in 14 subfamilies are listed. Compared to the North American catalog by Foote et al. (1965), 224 species are added, and there are 15 replacement names, 84 synonyms, 5 species removed from synonymy, and 76 transfers, as well as 10 species included in the previous catalog that are removed from the new list. Furthermore, 13 additional genera and 3 generic synonymies are included. Nomenclatural changes proposed in this catalog consist of 1 new generic synonymy, 4 new synonyms, 2 new names, 40 new combinations, and 1 species newly removed from synonymy. Additional nomenclatural changes and problems are discussed. All validly named taxa described before February 2004 are included. For each genus, the species list is preceded by notes on its distribution, biology, and ecology as well as a list of pertinent keys and revisions, when such information is available. For each valid species name, the list includes the author, year of publication, page number of original description, type depository and locality, and distribution in North America by state or province and occurrence in other realms, as well as taxonomic notes wherever applicable. Additional distribution records from the literature have been added. All known synonyms of genera and species as well as errors, emendations, and misidentifications are included. A bibliography of 492 publications is provided as well as an index to over 1838 included names. Statistics and comments on the history of North American dolichopodid research are presented. The diversity and distribution of Nearctic Dolichopodidae and their relationships with the fauna of other realms is tabulated and discussed.