The present techniques do not offer the possibility for milling and burnishing at the same time. The novelty of this study is the development of a new tool and tool holder that allows this processes to take place simultaneous. Magnesium alloys have a wide range of usages in industry; in the past years they seem to be a promising solution to classic implants. Improvements in fatigue and tensile strength need to be made. Heat treatments are difficult to implement, so the solution is a mechanical treatment. The burnishing process offers very good results, but it has difficulties in simultaneous machining with the milling process. Thereby a hydraulic roller burnishing tool and a special tool holder was manufactured to solve this issue. The combined process was carried out on a CNC milling machine. This study seeks to highlight the influence of the milling-burnishing process parameter on the surface roughness in the case of magnesium alloy AZ31B-F. Parameters like speed and feed of cut, burnishing pressure and depth where taken into consideration. It was noted that with the increase of the feed, speed, pressure and depth of burnishing the general percentage improvement of the surface roughness was higher.