In order to provide a printing unit (1; 50) of modular design with the lowest possible expenditure on construction and high flexibility, the printing unit (1; 50) of modular design for printing webs (29) has a stand (2; 2'; 54), which is provided with at least one crossmember (3; 4; 51) at both ends (drive and operating side), printing cylinders (9 to 16) being mounted in the crossmembers (3; 4; 51) in such a way that a structural unit comprising crossmembers (3; 4; 51) and printing cylinders (9 to 16) can be taken completely out of and put into the stand (2; 2'; 54).