In the present study, we have developed a convenient co-precipitation route using water as a solvent for stabilization of pure La2NiMnO6 (LNMO) nanoparticles. The structural stability of LNMO nanoparticles is achieved at lower temperature (∼600 °C) in relatively short time (6.5 h). X-ray diffraction data revealed a single-phase monoclinic structure with P21/n space group. Distortion in the unit cell is responsible for an overall decrease in the cell volume of LNMO nanoparticles as compared to that of its bulk counterpart. The band gap estimated for LNMO nanoparticles is 2.61 eV which is larger than that of the corresponding bulk system (1.4 eV). Transmission electron microscopy confirms that mean particle size is in the nanoscale range and has spherical morphology. A large decrease is observed in the Curie temperature for LNMO nanoparticles which is correlated with the structural distortion. Magnetic studies indicate that there is very little antiferromagnetic antisite disorder.