A two-dimensional pseudo-homogeneous model of wall-cooled fixed bed Fischer-Tropsch synthesis (FTS) reactor with Co/Re/γ-Al₂O₃ catalyst was developed to study the effect of process and design parameters on heat generation and removal characteristics. The influence of liquid-phase formation on heat transport was accounted for by using two-phase correlations. The effect of intraparticle diffusion on heat generation was considered. Detailed numerical simulations were performed to analyze the effect of process and design parameters on the reactor performance in terms of heat management. Results show that thermal behavior of FTS fixed bed reactors is very sensitive and any large disturbances can lead to temperature runaway. Large tube diameters are shown to be particularly unfavorable, with d _t >5 cm resulting in axial and radial gradients greater than 20 K and 13 K, respectively. The importance of detailed reactor modeling when designing and optimizing FTS fixed bed reactors is highlighted.