| Abbreviation | Definition |
|---|---|
| IUCH | Internation Union for Circumpolar Health |
| IUCH | International Union for Circumpolar Health |
| IUCH | International Union of Circumpolar Health |
| IUCN | Indian Union for Conservation of Nature |
| IUCN | International Union for Conservation Network |
| IUCN | International Union for Conservation of Nature |
| IUCN | International Union for Conservation of Nature and Natural Resources |
| IUCU | Idaho United Credit Union |
| IUCW | International Union for Child Welfare |
| IUD | Industrial Union Department |
| IUDC | Intercontinental Union of Disgusting Characters |
| IUDL | Indian Union Dalit League |
| IUEB | Iglesia Union Evangelica Belen |
| IUEC | International Union of Elevator Constructors |
| IUEF | International Union of Exhibitions and Fairs |
| IUEV | Internacia Unuigo de Esperantistaj Vegetaranoj |
| IUF | International Union of Food |
| IUGS | International Union of Geologic Sciences |
| IULA | International Union of Local Authorities |
| IUMI | International Union of Marine Insurance |