Abstract: A modular photovoltaic element for building roofs comprising: a lower hollow structural part of plastic material, an upper convex cover element of material transparent to sunlight and fixed to said hollow part, at least one photovoltaic cell mounted on a support and housed in a cavity defined by said hollow part and said convex cover element, an integrated current for controlling the operation of said element, a compartment which is separate from the cavity housing said photovoltaic cell, and which houses means for electrical connection to the adjacent modular element of the same row, partially superposed to cover said compartment, connection cables joined to watertight connectors positioned on the surmounting portions of adjacent hollow parts of one and the same row, said connectors being connected to said photovoltaic cell and to said integrated circuit, first mechanical means for connecting said cover element to said hollow part, second mechanical means for connecting said hollow part to the hollow part