This paper presents a novel load-flow method for unbalanced islanded ac microgrids. The principles of this method are based on the modified augmented nodal analysis (MANA) formulation. It is shown that it can considerably improve the performance over conventional mismatch equation-based solvers for islanded microgrids, while being more generic and simpler to formulate. An unbalanced 25-bus ac microgrid is used to verify the validity and efficiency of the proposed MANA-based formulation. The results are compared against mismatch formulation to demonstrate better computational speed and reduced number of iterations.