The future smart grid can have an AC/DC hybrid structure that enables the integration of AC/DC energy supply and demand, thus permitting the formation of AC/DC hybrid microgrids (HMGs). The AC/DC HMG is a promising concept that provides the envisioned smart grid with the plug-and-play feature. Nevertheless, understanding such hybrid systems, especially during islanding, require an accurate and robust load flow program. To this end, this paper proposes a novel robust power flow algorithm for isolated AC/DC HMGs. The power flow problem is formulated as a least-squares minimization problem, and solved using the Levenberg-Marquardt algorithm. The accuracy of the proposed load flow algorithm is validated against time domain simulation results, while its robustness is demonstrated on a highly-resistive network. The proposed load flow algorithm is expected to reveal the light for further studies on AC/DC HMGs.