The combination of the high hardness of the tungsten carbide with the fracture toughness of the cobalt binder makes the WC/Co composite an important material widely used in the tool industry. Its applications are as diverse as metal cutting, machining of metallic and nonmetallic materials, mining, construction, among others. Carbon nanotubes (CNTs) have unique physical and mechanical properties and are being incorporated in several ceramics, alloys, metals, in order to potentiate their properties. They were incorporated in the WC/Co combination, in order to evaluate their influence on the hardmetal properties. In the present study, the High Pressure and High Temperature method (HPHT) was applied as a consolidation technique, in which the WC-10 wt% Co mixture with 1 wt% CNTs was sintered under a temperature of 1200 °C and pressures of 4, 5 and 6 GPa. The sintering time was 5 minutes, divided into 3 cycles of 100 seconds each. Hardness values ​​and fracture toughness were obtained from the hardness test in order to evaluate the influence of the incorporation of CNTs on the mechanical properties of the hardmetal, as well as pressure variation. It was observed that with the increase of the pressure applied during the sintering, the hardness values were increased. However, with the incorporation of the CNTs, the hardness values were reduced, compared to the mixture without incorporation. For the WC/Co mixtures, the mean hardness values are: 11.67 GPa (4 GPa); 12.31 GPa (5 GPa) and 12.50 GPa (6 GPa). For the WC/Co/CNTs mixtures, the mean values of hardness were: 9.18 GPa (4 GPa); 10.38 GPa (5 GPa) and 10.54 GPa (6 GPa). The fracture toughness values, for the samples without the incorporation of CNTs, they remained close, even with the pressure change: 11,10 MPa.m^1/2 (4 GPa); 10,03 MPa.m^1/2 (5 GPa) e 10,07 MPa.m^1/2 (6 GPa). The same behavior was observed for samples with CNTs, but lower values of fracture toughness were obtained: 8,40 MPa.m^1/2 (4 GPa); 9,24 MPa.m^1/2 (5 GPa) e 8,52 MPa.m^1/2 (6 GPa). Microstructural analysis was performed using Confocal Laser Microscopy and Scanning Electron Microscopy, which evidenced a low sintering of the samples due to the high porosity presented by them. This situation can be verified by the densification of the samples, which obtained maximum values of 90,49%, for the sintered sample without CNTs, at 5 GPa and 87,05%, for the sample sintered with CNTs, at 4 GPa. It was concluded that the addition of CNTs did not benefit the analyzed mechanical properties of the hardmetal, considering the sintering methodology analyzed.