During the War of the Fifth Coalition, Bertoletti served in the Italian theater under the command of Eugène de Beauharnais, the Viceroy of Italy. At the outbreak of war, he led a brigade in Achille Fontanelli's Division. Later, Jean Rusca took command of the division, which missed the Battle of Piave River. Bertoletti led his brigade in an action at Klagenfurt on 8 June and at Papa, Hungary on 12 June, as well as the major Battle of Raab on 14 June. During the Battle of Wagram, his brigade defended Klagenfurt on Eugene's line of communications.