Operating conditions and selectivity of a new perovskite nanocatalyst were studied in Fischer‐Tropsch synthesis using a fixed‐bed microreactor. Selectivity equations were obtained using the experimental data collected from a hydrogenation process in a fixed‐bed microreactor. The operating conditions were obtained by defining the design‐of‐experiment scope based on response surface methodology, on 3 levels and in 15 tests. The optimum selectivity for alkenes relative to alkanes was obtained at 349.7 °C, 3.2 bar, and a H2/CO volumetric ratio of 1. Also, the optimum selectivity for alkenes relative to the overall selectivity for other products was attained at 250 °C, 2.3 bar, and a feed volumetric ratio of 2.