Abstract: A process for producing polyoxymethylene polymers comprises the reaction of aqueous formaldehyde solution with an aqueous solution of a base, wherein A) a starter solution comprising formaldehyde is initially charged and B) an aqueous formaldehyde solution and a base are added to the starter solution to obtain a reaction mixture. The starter solution in step A) has a temperature of ?40° C. to ?46° C. and the additions of the solutions in step B) are performed at a temperature of the reaction mixture of ?40° C. to ?46° C. The base is an alkali metal hydroxide and/or an alkaline earth metal hydroxide and the molar ratio of formaldehyde to base is ?55:1 to ?90:1 based on the total amounts of formaldehyde and base employed in the process. The base in step B) is added in aqueous solution.