Hybrid energy systems combine multiple energy conversion devices and are suitable options for isolated power generation. Such systems have no interaction with the grid. They serve the power needs of remote locations where the extension of the grid is infeasible. The design of such systems has several options. The units may include diesel generator sets, renewable energy based systems like solar photovoltaic panels, wind turbines or a combination of these systems with energy storage. In the present study, optimum design of biomass gasifier integrated hybrid systems is addressed. A multi-objective optimization approach minimizing cost of energy and unmet load fraction is illustrated. An exhaustive enumerative approach based on epsilon-constraint method is adopted for generating the Pareto front corresponding to the design problem. The software tool HOMER is used for the detailed simulation of the system configurations. The design approach is illustrated based on a case study corresponding to a remote location of Kerala in southern India. The proposed approach provides a useful tool for the design and planning of hybrid energy systems.