We report the Silver Lamprey (Ichthyomyzon unicupis) from Arkansas for the first time. Fifteen adult I. unicuspis attached to paddlefish (Polyodon spathula) were collected in Apr. 2005 from the White River near the confluence of the Black River, Independence and Jackson counties. Twelve (80%) of the I. unicuspis possessed 3 teeth (including the apex) in the anterior row, while the other 3 had 4 teeth in their anterior row; unicuspid teeth arrangement in the lateral row were 3 3 for 11 (73%) lampreys while 4 had 4 4 teeth in the lateral row. Two additional specimens collected in Apr. 1972 and May 1998 from the Buffalo and White rivers in Marion and Prairie counties, respectively, and originally identified as Chestnut Lampreys (Ichthyomyzon castaneus), were re-examined and identified as I. unicuspis. The addition of I unicuspis to the lamprey fauna of Arkansas brings to five the number of species currently occurring in the state.