In this study, the effect of tool wear on slot geometry was experimentally investigated in a micro-milling process. In the tests, Inconel 718 superalloy was selected as workpiece material and constant cutting parameters were considered. The tests were conducted under dry conditions and dimensional changes in micro-slots, burr formation and variations in cutting forces during/after consecutive cutting processes were investigated. According to the obtained results, peripheral wear formed on tool diameter increases with increasing cutting distance. An axial wear as well as the peripheral wear also forms on the cutting tool. Axial wear leads to variation of tool corner radius with the time. An increase in tool corner radius causes to deterioration of slot geometry and additional burr formation. In addition, the chips adhered to cutting tool also leads to an increase in tool corner radius. So, the cutting process turns into a ploughing dominant cutting process and the cutting forces increase.