Brief notes are given on the life and Diptera collection of Carl Fredrik Fallén (1764-1830). The 62 species-group names that he proposed in the present families Fanniidae and Muscidae are listed, their type-material and identities discussed, and lectotypes designated where appropriate. Primary types of 51 species are in Stockholm (Naturhistoriska Riksmuseum), 10 are in Lund (Museum of Zoology), and 1 is considered lost. 55 lectotypes are designated. Spilogona falleni sp. n. is described. The following 6 new synonyms are established: Hydrotaea armipes (Fallén, 1825) (syn. n.: occulta (Meigen, 1826)); Helina confinis (Fallén 1825) (syn. n.: anceps (Zetterstedt, 1838)); Phaonia errans (Meigen, 1826) (syn. n.: erratica (Fallén, 1825), preocc.); Phaonia laeta (Fallén, 1823) (syn. n.: trigonalis (Meigen, 1826)); Spilogona litorea (Fallén, 1823) (syn. n.: longipes (Ringdahl, 1918)); Mydaea urbana (Meigen, 1826) (syn. n.: rustica (Fallén, 1825), preocc.).