The driver rostering problem (DRP), arising in public bus transport companies, generates for each group of drivers a cyclic roster while management considerations, labor laws, and the preferences of drivers have to be satisfied. Optimal rosters are characterized by maximal satisfaction of drivers, minimal difference of overtime among all drivers, and minimal number of unassigned duties. The DRP is mostly solved sequentially due to its high complexity, namely firstly the rota scheduling problem, and secondly the duty sequencing problem. However, this method may generate sub-optimal rosters. In order to avoid a sub-optimal solution, the paper discusses an integrated DRP, which is solved for real-world instances and compared with the results of the sequential approach.