Mn-doped nanocrystalline ZnO particles have been successfully synthesized at low temperature (80?C) by the coprecipitation method using zinc sulfatehepta hydrate and NaOH. The structural and magnetic properties have been characterized using X-ray diffraction (XRD), Energy dispersive x-ray, vibrating sample magnetometer and electron spin resonance. XRD measurements revealed that the sample posses hexagonal wurzite structure. From the Rietveld refined XRD spectra, the lattice parameters, average crystallite size and microstrain values was obtained. In this range of doping concentrations all samples show an expansion of the lattice parameters relative to the bulk samples. From magnetic measurements we observed the presence of room temperature ferromagnetic order in our Mn-doped ZnO samples.