| Abbreviation | Definition |
|---|---|
| INADA | investigational new animal drug application |
| INCB | International Narcotics Control Board |
| IOB | Institute of Biology |
| IPBA | International Progressive Breeders' Alliance |
| IPC | International Policy Council (on Agriculture, Food and Trade) |
| IPG | Inter-Professional Group |
| IPS | International Primatological Society |
| IPSP | Inhibitory PostSynaptic Potential |
| IPVS | International Pig Veterinary Society |
| IRBA | International Reptile Breeders' Association |
| IRD | Independent Review of Dispensing |
| IRIS | International Renal Interest Society |
| IRRO | Information Resource for the Release of Organisms to the Environment |
| IRRP | International Registry of Reproductive Pathology |
| IRSNB/KBIN | Institut Royal des Sciences Naturelles de Belgique/ Koninklijk Belgisch Instituut voor Natuurwetenschappen |
| ISAZ | International Society for Anthrozoology |
| ISDVMA | International Sled Dog Veterinary Medical Association |
| ISER | International Symposia on Equine Reproduction |
| ISFAE | International Society for Farm Animal Endocrinology |
| ISG | Independent Scientific Group (advises government on the control of tuberculosis in cattle in the UK) |