This paper documents the robber fly fauna collected in lowland rainforest in the southwesternmost part of French Guiana (Mitaraka). A total number of 146 asilid specimens were collected during the Mitaraka 2015 survey. These asilids represent six subfamilies, 23 genera, 16 described species, 28 morphospecies, and first records of 12 genera and 29 species for French Guiana. The subfamily Laphriinae Macquart, 1838 is clearly best represented with 14 genera and 28 species (especially Atomosiini Lynch Arribálzaga, 1882 with nine genera and 18 species), followed by Leptogastrinae Schiner, 1862 with three genera and seven species, Asilinae Latreille, 1802 with three genera and four species, Ommatiinae Hardy, 1927 with one genus and three species and Dasypogoninae Macquart, 1838 and Trigonomiminae Enderlein, 1914 with one species each. Eighteen and 11 species were collected as singletons or doubletons respectively, accounting for about of all species observed. Pilica erythrogaster (Wiedemann, 1828) and Hybozelodes dispar (Hermann, 1912) (both Laphriinae) were collected in the largest numbers, but appeared to be restricted to a few sites. A six meter long Malaise trap yielded the largest diversity and highest numbers of asilids, accounting for over 2/5 of all species collected. Also the SLAM traps, the light trap and sweep netting were quite productive. A checklist of the French Guianan Asilidae is provided.