We have examined the structure and phase behaviour of strontium-doped Ce1-xSrxCoO3-delta and found that the perovskite form is stabilised over a relatively narrow solid solution range (x > 0.85). A combination of electron, powder X-ray and neutron diffraction has revealed tetragonal superstructures of the basic perovskite unit; (I4/mmm) 2a(p) x 2a(p) x 4a(p) (x = 0.90) and (P4/mmm) a(p) x a(p) x 2a(p) (x = 0.95). Magnetisation measurements show ferromagnetic behaviour under applied magnetic fields. Low temperature neutron diffraction of Ce0.10Sr0.90CoO2.80 in zero field reveals a magnetic cell of dimension 2ap x 2ap x 4ap with an ordered cobalt moment of 1.7 B.M. at 25 K. (c) 2005 Elsevier Ltd. All rights reserved.