The present invention relates to an aqueous dispersion of alkyd resin based on fatty acids possessing conjugated unsaturation which is treated with an oxidizing agent and which has a specific performance, in particular on drying, to a specific production process and to its use as binder in aqueous compositions for decorative or industrial coatings with a reduced level of drying agent or without drying agent.The aqueous dispersion comprises at least one alkyd resin, obtained from at least one unsaturated fatty acid having a level by weight of at least 5% of the said resin, which resin is treated, before and/or during and/or after the forming of the aqueous dispersion, with at least one oxidizing agent selected from: hydroperoxides, including H.sub.2O.sub.2, peroxides or singlet oxygen, and with the oxidizing treatment temperature being: i) from ambient temperature to less than 100.degree. C., when it takes place after the forming of the dispersion, and ii) from 50 to 150.degree. C., when it takes place before the forming of the dispersion, and iii) from 50 to less than 100.degree. C., when it takes place during the dispersion stage.