|Part of the Bosnian War|
|Commanders and leaders|
| Marijan Mareković
| Ratko Mladić
|Casualties and losses|
|49 killed (official figure)
60–80 killed (unofficial estimates)
Operation Una (Croatian: Operacija Una) was military offensive conducted by the Croatian Army (HV) during the Bosnian War. Following the success of Operation Storm which ended the Republic of Serbian Krajina and Operation Mistral in Western Bosnia and Herzegovina, Croatian president Franjo Tuđman, on the recommendation of Richard Holbrooke, ordered the offensive with the goal of crossing the Una and Sava Rivers thus creating favorable positions for a future push towards Prijedor and Banja Luka.
The operation was planned and executed hastily, which resulted in Croatian forces not having enough time to prepare for a river crossing operation, lacking appropriate means to do so, encountering a fast river flow with a high water level, and underestimating opposing Serbian forces not expecting a well organized defense.
The first failed attempts to cross the Sava happened near the village of Košutarica, and at Jablanac near Mlaka. The second set of attempts, on the 19th, happened near Jasenovac, Donja Gradina and Draksenić.
After Croatian forces suffered 27 killed in action in the first few hours of the operation, general Vinko Vrbanac who was sent to report on the situation, proposed ending the operation to prevent further casualties. Circumstances surrounding the operation remain controversial due to it possibly being politically motivated without proper military preparations and because of the losses which marked a first defeat for the Croatian forces since 1994.
In 2006 the County state attorney in Sisak started gathering information about the operation due to alleged war crimes committed by Croatian soldiers which resulted in the death of 40 Serb civilians.
- Marijan, Davor (2008). "Zborno područje Bjelovar u operaciji Una" [Operational zone Bjelovar in Operation Una]. Scrinia Slavonica (in Croatian) 8 (1): 317–335.
- Hedl, Drago (22 September 2010). "U operaciji Una 1995. poginulo je 49 vojnika. Zbog koga je sve pošlo po zlu?". Jutarnji list.
- Šoštarić, Eduard (14 August 2006). "Otvorena istraga zbog akcije 'Una'". Nacional.