Promoted to "Feldmarschall-Leutnant" (lieutenant general) in October 1799, Vukassovich took part in the 1800 Italian campaign. When Bonaparte invaded Italy via the Great Saint Bernard Pass, he commanded a division farther east in the area of Lake Maggiore and Lake Como. On 25 May, a cavalry patrol of Vukassovich's scouts briefly captured Bonaparte before themselves becoming prisoners when the French general's escort appeared. The sudden French offensive drove Vukassovich's outnumbered troops out of Milan. Pursued by Guillaume Duhesme's French corps, he retreated to Brescia and Cremona with his remaining 4,000 men, missing the Battle of Marengo.