Present experimental investigation focuses on implementing passive cooling thermal management technique using heat sinks filled with paraffin wax as phase change material (PCM). Al2O3 nanoparticles are dispersed as thermal conductivity enhancer (TCE) in different weight fractions (φ) for improved performance in the PCM. Unfinned and two finned heat sinks are used in this investigation. Experimental analysis is performed on different configurations of heat sinks and nano-enhanced phase change materials (NePCMs) consisting various weight fraction of Al2O3 nanoparticles (φ = 0%, 0.5%, 4%, and 6%) for a constant heat flux of 2.0 kW/m2. Results show that latent heat and specific heat capacity decreases with increase in the Al2O3 nanoparticle loading. Addition of Al2O3 nanoparticles in the PCM results in the reduced melting time of PCM. While, pure PCM based heat sinks keeps heat sink base temperature lower for longer time duration.