In May 2008 Sliven were promoted to the top flight winning the Eastern group of Bulgaria's second division. In their first year after returning to the elite, season 2008-09, OFC Sliven managed to finish in 12th place, thus avoiding relegation. The team managed to win eight games as well as to draw eight games, earning them 32 points. These results put them six points above Vihren Sandanski, who were relegated. From the eight wins that Sliven achieved, five were from home games, as well six of the draws, while at away games, Sliven managed to win three games and draw twice. Among these wins, Sliven managed to beat Bulgarian powerhouse CSKA Sofia 3-1 at home, as well as winning 3-1 against Botev Plovdiv, a traditionally strong side in Bulgarian football. This first season in the elite was under the management of Georgi Dermendzhiev, who would later coach Ludogorets Razgrad.