The invention relates to a process for the isolation of (per)fluorinated polymers containing sulfonyl fluoride functional groups from a polymerization latex. The process comprises adding the polymerization latex to an aqueous electrolyte solution under high shear stirring at a temperature equal to or lower than the glass transition temperature of the polymer. The invention further relates to the (per)fluorinated polymers containing sulfonyl fluoride functional groups isolated by the process and characterised by a loss of weight at 200° C. lower than 1% as determined by thermogravimetric analysis.