A modular rolling mill has a mill pass line along which products are rolled in a rolling direction. The rolling mill comprises first gear units arranged along a first line parallel to the mill pass mill line. Each first gear unit is driven individually by a motor and has a pair of mechanically interconnected output shafts. Second gear units are arranged along a second line between and parallel to both the first line and the mill pass line. Each second gear unit has a pair of mechanically interconnected input shafts driving a pair of output shafts. Rolling units are arranged in succession along the mill pass line. Each rolling unit is driven by an input shaft and has a pair of mechanically interconnected roll shafts carrying work rolls. First couplings connect the output shafts of each first gear unit to input shafts of two successive gear units, and second couplings releasably connect the output shafts of the second gear units to the input shafts of two successive rolling units.