A physical mixture of alkali-promoted iron catalyst with binder based on Fischer-Tropsch synthesis and an acidic co-catalyst (HZSM5) for syngas conversion to hydrocarbons was studied in a fixed bed micro reactor. Deactivation data were obtained during the synthesis over a 1400 h period. The deactivation studies on iron catalyst showed that this trend followed the phase transformation Fe2.2C ( ε′) → Fe5C2 (χ) → Fe3C (θ), and the final predominant phase of the catalyst was Fe3C (θ). Deactivation of zeolite component in bifunctional catalyst may be caused by coking over the zeolitic component, dealumination of zeolite crystals, and migration of alkali promoters from iron catalyst under synthesis conditions. The deactivation rate of iron catalyst was also obtained. A physical mixture of alkali-promoted iron catalyst with binder based on Fischer-Tropsch synthesis and an acidic co-catalyst (HZSM5) for syngas conversion to hydrocarbons was studied in a fixed bed micro reactor. Deactivation data were obtained during the synthesis over a 1400 h period. The deactivation studies on iron catalyst showed that this followed the phase transformation Fe2.2C (ε ’) → Fe5C2 (χ) → Fe3C (θ), and the final predominant phase of the catalyst was Fe3C (θ). Deactivation of zeolite component in bifunctional catalyst may be caused by coking over the zeolitic component, dealumination of zeolite crystals, and migration of alkali promoters from iron catalyst under synthesis conditions. The deactivation rate of iron catalyst was also obtained.