It is shown that active catalysts for Fischer-Tropsch synthesis with a controlled size of the particles of the dispersed phase may be formed on the basis of reverse microemulsions in a slurry reactor. After optimization of the composition of the reverse microemulsion (iron nitrate nonahydrate as a precursor of the active metal and SPAN-80 as a surfactant, 5 wt %), the size of the microemulsion droplets decreases to 130 nm. The chosen method for the synthesis of catalytic systems makes it possible to introduce promoters without any marked enlargement of the dispersed phase (130-160 nm). High-temperature Fischer-Tropsch synthesis is performed in a slurry reactor using catalysts prepared from reverse iron-containing microemulsions. The tested iron-containing catalytic systems feature high selectivity (up 73 wt %) in the formation of gasoline fractions (the C-5-C-10 fraction) that contain an abnormally high (up to 77 wt %) level of unsaturated hydrocarbons.