The flow field in the tip clearance region is dominated by a complex flow structure of secondary flows and vortices. The internal losses in this region have a strong influence on the compressor performance and the operational range, between the stall and choke points. Therefore, it is of major importance to study and treat the tip clearance region with the aim of improve the performance of the axial compressor. In this work, a circumferential grooves casing treatment was implemented in the NASA Rotor 37 transonic axial compressor with the objective of studying its influence on the tip clearance flow and the compressor performance. Numerical simulations were first conducted in the compressor without the casing treatment and the results obtained were compared with the experimental data. Subsequently, the casing treatment considering the circumferential grooves was implemented. Four different configurations (G1, G2, G3 and G4) of circumferential grooves were evaluated, the first of them with a single circumferential groove, and the next three adding one circumferential groove at a time. A set of simulations was carried out and the data obtained was compared with the simulations carried out previously for the smooth wall case. Finally, the effects of the casing treatment on the axial compressor performance and the flow in the tip clearance region were analyzed. The different configurations of casing treatment with circumferential grooves proposed in this work presented an increase of the operational range of the compressor, for the design rotational speed. Due to a larger resistance created to the flow that leaks in the tip clearance region of the compressor, from the rotor blade pressure side to the suction side, the generated entropy is greater than the one for the case without groove, providing a drop in the compressor efficiency in relation to the case without groove. For the peak efficiency point, without groove, it was verified drops of: 0,3% (G1); 0,69% (G2); 0,7% (G3); 0,7% (G4). Regarding the operational range of the compressor, with grooves, it was observed an increase with respect to the smooth wall case, with: 0,53% (G1); 1,02% (G2); 1,64% (G3); 2,63% (G4). The implementation of grooves also raised the pressure ratio for the operational points near the stall point.