Martignana di Po (Casalasco-Viadanese: ) is a comune (municipality) in the Province of Cremona in the Italian region Lombardy, located about southeast of Milan and about southeast of Cremona.
Martignana di Po borders the following municipalities: Casalmaggiore, Casteldidone, Colorno, Gussola, San Giovanni in Croce, Sissa Trecasali.