  We report on a small angle neutron scattering study of the vortex lattice in
overdoped La{2-x}Sr{x}CuO{4} (x=0.2) up to high magnetic fields (9.5 Tesla)
applied perpendicular to the CuO2 planes. At low magnetic fields we observe a
crossover from hexagonal to square coordination of the vortex lattice. This
field-induced transition confirms the results obtained in slightly overdoped
La{2-x}Sr{x}CuO{4} (x=0.17).
