A high-pressure atomiser nozzle, comprising: - an inlet which can be fluidically connected with means for supplying a high-pressure liquid; - an outlet for the spray of atomised liquid; - a fluidic connection line extending between said inlet and said outlet comprising: - at least one first duct defining an axis fluidically connected with said inlet; - an operating chamber arranged downstream of said at least one first duct; - a plurality of first openings for fluidically connecting said at least one first duct and said operating chamber configured so that the liquid flows from the first duct into the operating chamber; wherein said at least one first duct, operating chamber and first openings are mutually configured so that the flow of the high-pressure liquid in said operating chamber is of turbulent type; characterized in that said operating chamber comprises a single outlet opening with small section so that the high-pressure liquid flowing out therefrom is atomised liquid, said operating chamber having a side wall which includes said first openings, the latter extending parallel or slightly inclined with respect to said axis in order to have a slot configuration, so that the liquid flow flows into said operating chamber transversely with respect to said axis; and further characterized in that said operating chamber comprises a first substantially flat area perpendicular to said axis which includes said single opening, the latter and said first substantially flat area defining a sharp edge, said single opening preferably comprising a lateral surface coaxial with said axis which forms a substantially right angle with said fist substantially flat area. - an inlet which can be fluidically connected with means for supplying a high-pressure liquid; - an outlet for the spray of atomised liquid; - a fluidic connection line extending between said inlet and said outlet comprising: - at least one first duct defining an axis fluidically connected with said inlet; - an operating chamber arranged downstream of said at least one first duct; - a plurality of first openings for fluidically connecting said at least one first duct and said operating chamber configured so that the liquid flows from the first duct into the operating chamber; - at least one first duct defining an axis fluidically connected with said inlet; - an operating chamber arranged downstream of said at least one first duct; - a plurality of first openings for fluidically connecting said at least one first duct and said operating chamber configured so that the liquid flows from the first duct into the operating chamber; wherein said at least one first duct, operating chamber and first openings are mutually configured so that the flow of the high-pressure liquid in said operating chamber is of turbulent type; characterized in that said operating chamber comprises a single outlet opening with small section so that the high-pressure liquid flowing out therefrom is atomised liquid, said operating chamber having a side wall which includes said first openings, the latter extending parallel or slightly inclined with respect to said axis in order to have a slot configuration, so that the liquid flow flows into said operating chamber transversely with respect to said axis; and further characterized in that said operating chamber comprises a first substantially flat area perpendicular to said axis which includes said single opening, the latter and said first substantially flat area defining a sharp edge, said single opening preferably comprising a lateral surface coaxial with said axis which forms a substantially right angle with said fist substantially flat area.