Abstract: A method of producing acrolein comprising evaporating acetaldehyde and formaldehyde in the presence of diphenyl-N-nitrosamine taken in an amount of from 0.1 to 3 wt. %. The resultant vapors of said aldehydes are fed for aldol condensation which occurs in a gaseous phase on a catalyst, viz., coarsely porous silica gel promoted by 10 to 12 wt. % sodium silicate at a temperature of from 270.degree. to 300.degree. C. in the presence of diphenyl-N-nitrosamine taken in a quantity of from 0.1 to 3 wt. %. The resultant gas mixture formed at the stage of aldol condensation, containing acrolein, acetaldehyde, formaldehyde and water is cooled to obtain a condensate. Said condensate is subjected to rectification in order to isolate a mixture of acrolein with acetaldehyde and water, and an aqueous formaldehyde solution. Said aqueous formaldehyde solution is concentrated and returned to the aforesaid evaporation stage.