Nonsteroidal anti-inflammatory drugs (NSAIDs) are a group of heterogeneous compounds extensively used in both human and veterinary medicine for their antipyretic, anti-inflammation, and analgesic properties. NSAIDs consist of a wide range of pharmacologically active agents with different chemical structures, with similar therapeutic and adverse effects. The ASPCA Animal Poison Control Center received 22,206 NSAID incidents in dogs and cats (3% of total cases; dogs [15,823] and cats ) during 2005 to 2010. This is roughly equivalent to 4% NSAID incidents reported in humans. The most common NSAID involved was ibuprofen, followed by aspirin, naproxen, deracoxib, meloxicam, diclofenac, piroxicam, indomethacin, nabumetone, and etodolac. This article provides a brief overview of classification, mechanism of action, pharmacologic and toxicologic properties, and treatment information involving frequently encountered human and veterinary NSAIDs in dogs and cats.