This report describes adenovirus infections in nine colubrid snakes, including four com snakes, Elaphe gutatta; three milk snakes, Lampropeltis triangulum ssp.; one bull snake, Pituophis catenifer sayi; and one California kingsnake, Lampropeltis getulus californiae. Age ranged from neonate to 11 months, and average age was 5 months, although age was not known for one corn snake. Reported clinical signs included inappetence (seven), regurgitation (two), and coelomic distention (two). The only reported gross lesion was a small amount of fluid in the coelomic cavity of two snakes. Histologic examination was performed on five snakes, and characteristic large basophilic or amphophilic inclusions were seen in mucosal epithelial cells of the intestine (five), stomach (two), and esophagus (one), and in hepatocytes (two). The presence of inclusions was associated with enteritis (five), hepatic necrosis (two), and secondary bacterial septicemia associated with the gut lesions (three). Three snakes were emaciated or in suboptimal nutritional status by the time they died or were euthanized. Electron microscopy performed on intestinal, gastric, or hepatic tissue from five snakes identified adenovirus particles within intranuclear inclusions from each snake. Consensus polymerase chain reaction (PCR) and sequencing were used to identify two novel adenoviruses in the genus Atadenovirus from five snakes, including the bull snake, and four additional snakes from the same collections (one California kingsnake and three milk snakes). PCR amplification of frozen tissues had a much higher success rate than amplification of formalin-fixed tissues. This study shows diversity amongst adenoviruses of snakes, and further work to understand pathology and host/virus relationships of snake adenoviruses is indicated.