We have studied the structural, electrical and magnetic properties of La0.5Sr05C0O3 nanoparticles. The sample shows a size induced metal-insulator transition. The magnetoresistance of all the samples shows a monotonic increase with the field. The field cooled (FC) and zero field cooled(ZFC) magnetization display a broad paramagnetic-ferromagnetic transition at Tc with a large magnetic irreversibility. The observed frequency dependent shoulder in the in-phase(χ′) and the hump in the out of phase(χ″) part of the ac susceptibility indicate the glassy nature of the samples. © 2008 American Institute of Physics.