As a part of the conference ITAT 2017, the 5th international workshop “Computational Intelligence and Data Mining” has been organized. It is aimed at participants with research interests in any of these related areas, especially at PhD students and postdocs. Interested participants were invited to submit a paper in English of up to 8 double-column pages, prepared according to the instructions at the ITAT 2017 web pages. As this workshop started, 4 years ago, it had only 7 regular submissions. However, the interest in the computational intelligence and data mining workshops has been gradueally incereasing since that time. This year, we have 2 invited talks by internationally renowned esxperts, and 17 regular papers had been submitted to the workshop, among which 16 have been accepted for oral presentations and for inclusion in these proceedings. A key factor influencing the overall quality of a workshop and of the final versions of the submitted papers is the workshop's program committee. The 5th international workshop “Computational Intelligence and Data Mining” is grateful to the 27 reviewers from 10 countries who read the submitted papers, and have provided competent, and in most cases very detailed, feedback to their authors. Most of them have a great international reputation witnessed by hundreds of WOS citations.