We collected 2 species of Monogenoidea from the gills of 9 of 29 (31%) Rainbow Darters (Etheostoma caeruleum) from Arkansas. We found Gyrodactylus etheostomae on 4 of 29 (14%) from 3 localities and Aethycteron caerulei on 7 of 29 (24%) from 4 localities. These are the first records for A. caerulei from Arkansas and the first for parasites from E. caeruleum west of the Mississippi River. Based on geographic distribution and morphological similarity, we suggest amending the following previously reported host records for G. etheostomae as follows: Etheostoma asprigene to Etheostoma exile in North Dakota and Etheostoma radiosum tentatively to Etheostoma uniporum in Arkansas.