We present synthesis of Cobalt nanoparticles dispersed in toluene by laser ablation and their optical limiting properties with nanosecond laser pulses. Absorption spectra and concentration dependent optical limiting studies on nanoparticles indicate it as a versatile optical limiter. Cobalt nanoparticles show better optical limiting compared to the reference optical limiter fullerene C-60. Optical limiting threshold of Cobalt nanoparticles is about three times less than that of C-60. Z-scan experiments, angle dependent scattering, intensity dependent transmission, and temporal profile measurements indicate that the non-linear absorption, nonlinear scattering and thermal nonlinear refraction are responsible for optical limiting behavior of Cobalt nanoparticles. (C) 2012 Elsevier B. V. All rights reserved.