This paper presents a study of transverse and longitudinal arithmetic average roughness of carbon fiber-reinforced plastic (CFRP) material slotted with three micrograin carbide knurled tools: fine, medium, and coarse toothings. By transverse (respectively longitudinal) arithmetic average roughness, we mean roughness measured perpendicular to the advance direction (respectively in the advance direction). The purpose of this work is to implant a theoretical model of transverse arithmetic average roughness highlighting his dependence on only tool geometry, to validate it experimentally and to define an empirical model of longitudinal arithmetic average roughness for each knurled tool. From the results of ANOVA, it is concluded that feed per tooth makes the highest statistical and physical influence on surface roughness. Experiments show that knurled tool fine toothing is the suitable tool for slotting of CFRP because it produces less damage to the laminate plate.