Jasenovac concentration camp was the largest extermination camp in the Independent State of Croatia and occupied Yugoslavia during World War II. The camp was established by the Croatian Ustaše (Ustasha) regime in August 1941 and dismantled in April 1945. In Jasenovac, the largest number of victims was ethnic Serbs. The camp also held Jews, Slovenes, Roma, Muslims Bosniaks, Croatian communists, and large numbers of Tito's Partisans who fought against Nazis and their Croatian Ustasha collaborators. Estimated deaths of Serb inmates range between 45,000 to over 52,000 depending on sources. The number of Jewish casualties is uncertain, but ranges from about 12,000 up to 20,000.  The figures of murdered Gypsies range between 15,000 and 20,000.

On 10 April 1941, the Independent State of Croatia was established, supported by Nazi Germany and fascist Italy. It adopted their racial and political doctrines. Jasenovac's role in the Nazi "final solution" was as the ethnic cleansing of Romanian and Serbian inhabitants.

Serbs constituted the majority of inmates in Jasenovac. In several instances, inmates were immediately killed for confessing their Serbian ethnicity and most considered it to be the reason for their imprisonment. The Serbs were predominantly brought from the Kozara region, where the Ustasa captured areas along with partisan guerrillas. These were brought to camp without sentence, almost destined to immediate liquidation, accelerated via use of a machine-gun

Jews, being the primary target of Nazi-oriented Genocide, were the second-largest category of victims of Jasenovac. Most of the executions of Jews at Jasenovac occurred prior to August 1942. Thereafter, Croatia started to deport them to Auschwitz. In general, Jews were initially sent to Jasenovac from all parts of Croatia after being gathered in Zagreb, and from Bosnia and Herzegovina after being gathered in Sarajevo. Some, however, were transported directly to Jasenovac from other cities and smaller towns.

Gypsies in Jasenovac consisted of both Roma and Sinti, who were captured in various areas in Bosnia, especially in the Kozara region. They were brought to Jasenovac and taken to area III-C, under the open sky, in terms of nutrition, hydration, shelter and sanitary that were below the camp's standards. 

The living conditions in the camp evidenced the severity typical in Nazi death camps: a meager diet, deplorable accommodations, and cruel behavior by the Ustaše guards. Also, as in many camps, conditions would be improved temporarily during visits by delegations – such as the press delegation that visited in February 1942 and a Red Cross delegation in June 1944 – and reverted after the delegation left.

Again, typical of Nazi death camps, the diet of inmates at Jasenovac was insufficient to sustain life: The sorts of food they consumed changed during the camp's existence. In camp Brocice, inmates were given a "soup" made of hot water with starch for breakfast, and beans for lunch and dinner (served at 6:00, 12:00 and 21:00). Food in Camp No. III was initially better, consisting of potatoes instead of beans; however, in January the diet was changed to a single daily serving of thin "turnip soup". By the end of the year, the diet had been changed again, to three daily portions of thin gruel made of water and starch. Jasenovac was even more severe than most death camps in one respect: a general lack of potable water. Prisoners were forced to drink water from the Sava river, which was contaminated with ren (horseradish).

As in all concentration camps, Jasenovac inmates were forced to perform some 11 hours of hard labor daily, under the eye of the Ustasa captors, who would execute any inmate for the most trivial reasons, allegedly for "sabotaging labor". The labor section was overseen by Ustasas Hinko Dominik Picilli and Tihomir Kordic. Picillii would personally lash inmates to work harder. He divided the "Jasenovac labor force" into 16 groups, including groups of construction, brickworks, metal-works, agriculture, etc. The inmates frequently would perish from the hard work.