Pretreatment processes for stable gas condensates are examined to increase the yield of light fractions and to improve product quality at primary refineries. Effects of pretreatment with a constant magnetic field of a stable gas condensate in flow mode with filtration through titanium-fiber filters on the feedstock disperse phase and atmospheric-distillation product yield and quality are studied. It is shown that the yield of light fractions increases by 4-13 wt% after treatment with magnetic field of various strengths; by 7-16 wt% with subsequent filtration. The octane number of the gasoline cut increases by 4-10 points. The cooking capability of the residue decreases by 1.1-1.7 times depending on the gas-condensate pretreatment process. The system dispersion increases after treatment with the magnetic field, which has a positive effect on the atmospheric-distillation product yield and quality.