The simulation and evaluation of several biomass-to-liquid processes using gasification and Fischer-Tropsch (FT) synthesis was conducted using Aspen Plus. Three different process were simulated based on different conditions of FT synthesis. High temperature and low temperature FT synthesis was included. Two low temperature FT synthesis based process were conducted, one using Fe-based catalyst, the other using a Co-based catalyst. Due to different FT product distributions, different final product profiles were obtained. The processes focused on diesel and gasoline like biofuels as well as methane production. Thereafter, the processes were economically evaluated and compared. Based on the results, low temperature FT synthesis using a Co-based catalyst was the most optimal one. Lastly, optimisation and design of two main processing units, the main distillation column and the fractional distillation column were performed for the Co-based catalyst low temperature FT synthesis case in order to optimise its performance. As a result, the equipment cost for the process was reduced by a total of 175.000 $.