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We report on the observation of remarkable room-temperature ferromagnetism in epitaxial (Zn,Mn)O films grown by a pulsed-laser deposition technique using high-density targets. The optimum growth conditions were demonstrated from x-ray measurements, microstructure, Rutherford backscattering, micro-Raman, and magnetic studies. Superior ferromagnetic properties were observed in (Zn,Mn)O films grown at a substrate temperature of 500 °C and with an oxygen partial pressure of 1 mTorr. Ferromagnetism becomes weaker with increasing substrate temperature due to the formation of isolated Mn clusters irrespective of higher crystalline quality of the film.