Small rodents are common exotic companion animal pets, but due to size, high metabolic rates, and requirements for sedation/anesthesia for handling or completing diagnostic testing, these species can be challenging to diagnose and treat appropriately. This masterclass will provide an overview of common emergency presentations of disease processes including: respiratory, gastrointestinal, dermatologic, and renal systems, neoplastic diseases, and zoonoses in rats and mice, as well as, discuss important anatomical and physiological differences between species, common clinical techniques, diagnostic imaging, and anesthesia/sedation strategies. The goal of this masterclass is to and provide information about emergent management and current medical updates in rats and mice for both the general practioner and referral level providers.