To provide a process for producing a liquid composition in which formation of a fluorinated polymer having ion exchange groups with a relatively large particle size is suppressed; a process for producing a catalyst layer-forming coating liquid capable of forming a catalyst layer in which inclusion of foreign matters is suppressed; and a method for producing a membrane/electrode assembly by which a catalyst layer or a polymer electrolyte membrane in which inclusion of foreign matters is suppressed, can be formed. A process for producing a liquid composition, which comprises holding a fluorinated polymer having -SO 2 F groups at from 140 to 160°C for at least 45 minutes; cooling the fluorinated polymer having -SO 2 F groups held at from 140 to 160°C to less than 110°C at a rate of at least 50°C/min; converting the -SO 2 F groups in the fluorinated polymer having -SO 2 F groups cooled to less than 110°C to ion exchange groups to obtain a fluorinated polymer having ion exchange groups; and mixing the fluorinated polymer having ion exchange groups and a liquid medium.