The paper considers UAV path following guidance system design. The main feature of this paper involves incorporating dynamics of the closed-loop system consisting of UAV with inner loop autopilot as structural components of the overall guidance system. The outer loop of the guidance system is the path following system using lateral acceleration control. In the majority of publications devoted to the path following guidance the inner loop dynamics was neglected or simplified as much as possible. The mathematical model of the entire guidance system, including the inner and the outer loops dynamics, was determined. To improve performance and robustness of the developed guidance system H-2/H-infinity-parametric robust optimization procedure is applied. The efficiency of the proposed approach is demonstrated by model-in-loop simulation.