A two-stroke engine, comprising: a crankcase; a cylinder connected to said crankcase; a combustion chamber defined by a reciprocally mounted piston within said cylinder; a crankshaft mounted rotatably in said crankcase and drivingly connected with said piston; at least one overflow passage connecting the crankcase and the combustion chamber when the piston is positioned in the lower dead center region; a connecting stub attached to said cylinder which contains an intake passage that opens into the crankcase and supplies fuel and combustion air, said intake passage including therein an air-fuel mixture passage, wherein said connecting stub contains at least one section of the mixture passage; at least one fuel opening for supplying fuel into said mixture passage; and a guiding rib positioned within said connecting stub and oriented longitudinally in the mixture passage and protruding into the mixture passage.