The system of La1–xSrxCo0.5Mn0.5O3 solid solutions have been studied by neutron diffraction and the measurement of the magnetization. The composition with x = 0 has the monoclinic structure (space group P21/n); the compositions with 0.15 ≤ x ≤ 0.6 are rhombohedral (R $$\bar 3$$ 3 ¯ c), and the composition with x = 0.75 is cubic (Pm $$\bar 3$$ 3 ¯ m). All the compositions with x ≤ 0.75 are shown to contain a ferromagnetic component. The stoichiometric composition with x = 0.5 undergoes a sharp ferrromagnet–paramagnet transition at 240 K; however, no coherent magnetic contribution to the neutron diffraction has been detected. The magnetic data are interpreted, assuming that the ferromagnetism at x ≤ 0.15 is due to positive superexchange Co2+–O–Mn4+ interaction, while, at x ≥ 0.25, the superexchange interaction between ions Co3+ in a high-spin state and ions Mn4+ is responsible for the ferromagnetic component.