| Popeni | |
| Name Other: | Ursoaia |
| Pushpin Map: | Romania |
| Subdivision Type1: | Country |
| Subdivision Name1: | Romania |
| Subdivision Type2: | Counties |
| Subdivision Name2: | Bacău County |
| Subdivision Type3: | Villages |
| Subdivision Name3: | Popeni |
| Length: | 22km (14miles) |
| Mouth: | Trotuș |
| Mouth Location: | Boiștea |
| Mouth Coordinates: | 46.1929°N 26.9587°W |
| Basin Size: | 65km2 |
| Tributaries Right: | Secul |
The Popeni (also: Ursoaia) is a right tributary of the river Trotuș in Romania.[1] It discharges into the Trotuș in Boiștea. Its length is 22km (14miles) and its basin size is 65km2.