Big Brother 4 was the fourth season of the reality show Big Brother in Bulgaria. It was aired on Nova Television and Nova+. The show launched on 22 September 2008, 20:00 h and continued for 3 months (12 weeks), ended on 14 December 2008, lasted for 84 Days - the shortest regular Big Brother season so far in Bulgaria (although Big Brother 3 was just one day longer). Milen Tsvetkov was the host of Big Brother 4. The money prize was 300 000 leva, which was the highest in the history of Big Brother Bulgaria (winners from the previous three seasons won 200 000 leva each). Veneta Raykova (a former Housemate from VIP Brother 2), who was pregnant during the show, was the host of a new late talk-show called Little sister. Rumen Lukanov was the host of the interactive part of the show (voting). The show was aired at 20:00 h from Monday to Saturday (live shows are on Monday and Thursday), and after 22:30 on Sunday. Nova+ aired live footages at 10:00, 13:00, 16:00, 19:00 and 22:30. Repetitions of the episodes aired on Nova Television were broadcast at 18:00 the next day. The talk show Little sister was aired on Monday and Thursday at 23:45.
From 22 June until 22 July auditions were held in the ten biggest cities in Bulgaria - Pleven, Veliko Tarnovo, Rousse, Shumen, Varna, Bourgas, Stara Zagora, Plovdiv, Blagoevgrad and Sofia. 13 955 candidates in total showed, 2700 of which were in Sofia. The third and final round of the auditions was held in Sofia from 20 July to 10 August, with 415 candidates. On 15 September, 10 of the Housemates were isolated in separate secret places. 10 women entered the House on 22 September. Originally, an eleventh Housemate - Neli was expected to enter the House. However, she lost consciousness before entering the show and was decided not to take part in Big Brother 4. Instead, Violeta entered the show the next day.