Michael III Doukeianos (; Dulchiano in Italian), called the Young, was the catepan of Italy from 1040 to 1041. He replaced Nikephoros Doukeianos. His first major act was to offer the rule of Melfi to the Greek-speaking Lombard Arduin with the title topoterites. However, Arduin soon betrayed him and led his Norman mercenaries in support of the Apulian rebellion of Argyrus. On March 16, 1041, near Venosa, on the Olivento, he met the Lombard-Norman army but was defeated.