Process for the preparation of a dispersion based on homopolymers/copolymers of tetrafluoroethylene (TFE), said dispersion having a bimodal or multimodal distribution of the particle diameters, wherein the fraction of small particles is in the range 1.5-359 by weight calculated on the dry product; the ratio between the average diameter of the small particles with respect to the average diameter of the dispersion obtained from the polymerization being in the range 0.02-0.6; said process comprising the following essential steps: (a) preparation of an aqueous microemulsion comprising fluorinated surfactants and (per)fluoropolyether oils (PFPE); (b) feeding of the microemulsion into the polymerization reactor; (c) feeding of at least one fluorinated surfactant.