The thermal performance of a new two-phase device developed for electronics cooling was experimentally investigated in this research. The proposed device is flat and composed of eight channels, where two parallel channels, one of which is partially filled with a sintered metallic porous medium, are interconnected, forming four parallel loop heat pipes. The wick structure promotes working fluid displacement along the device. Diffusion bonding was the manufacturing process. A benchmark flat pulsating heat pipe was also manufactured and experimentally studied for thermal performance comparison. Distilled water was used as the working fluid. Heat transfer rates from 10 to 170 W were applied to the flat heat pipes at gravity-assisted and horizontal orientations. The experimental results showed that the proposed flat loop heat pipes in parallel arrangement operated successfully in a wide thermal load range at the gravity-assisted position, reaching an almost constant thermal resistance of 0.17±0.02 °C/W between 80 and 170 W. In the horizontal orientation, the new device worked satisfactorily at low heat loads, with a minimum thermal resistance of 0.39±0.11 °C/W at 24 W. On the other hand, the conventional pulsating heat pipe operated adequately for high power inputs, presenting the lowest thermal resistance of 0.11±0.01 °C/W at 170 W. The major conclusion is that the proposed two-phase flat loop heat pipes in parallel arrangement behave successfully in a specific thermal load range for each orientation, being considered a suitable cooling alternative for flat electronic devices.