This special issue brings peer reviewed selection of results presented at 13th International Symposium on Operations Research, SOR'15, that took place in Bled, Slovenia in September [23][24][25] 2015. The participants at this conference came from many countries but the majority was from Central Europe. In nearly hundred talks, they have presented state-of-the-art results in several emerging areas, like complex networks, high performance computing and big data analysis. Beside these issues, new results in traditional areas like inventory planning, econometric modelling, multi-criteria decision making and mathematical programming were presented.The talks were supported by publications of short, at most 6 pages long, papers printed in the conference proceedings (Zadnik Stirn et al. 2015), which finally contained 93 papers/abstracts written by 191 authors. All authors were also invited to submit the extended and modified version of conference papers or new scientific papers covering topics in operations research for a special issue of Central European Journal of Operations Research by January 31, 2016. Although, the call was open at the conference SOR'15, the submissions that were not necessarily presented at the conference were welcomed as well. In the due time 15 papers were received and a peer review process according to highest academic standards started. After several rounds of major and minor revisions the editorial board of guest editors accepted 12 papers for publication in this special issue.The accepted papers cover wide range of applications: multi-criteria decision making, heuristics and meta-heuristics, routing and scheduling problems and new approaches to solve selected mathematical optimization problems.