The presence of inhomogeneous magnetic clusters in Nd0.5CaxSr0.5-xMnO3 (x = 0.1 and 0.3) system has been investigated by dc magnetic susceptibility, magnetoresistance (MR) and ESR studies. The nature of magnetic transitions is found to be of second order in x = 0.1 and is of first order in case of x = 0.3 composition. The ferromagnetic clusters in the paramagnetic region show the signature of Griffiths-like phase for the x = 0.1 sample. The onset of predominant charge-ordered antiferromagnetic correlations above TC results in the deviation from Curie-Weiss law as an upturn in the magnetic susceptibility of x = 0.3 sample. The competition between the FM/AFM interactions arising from A-site cation disorder leads to quenched disorder in this system. © 2008 Elsevier Masson SAS. All rights reserved.