  We present late-time optical and mid-infrared observations of the Type-II
supernova 2003gd in NGC 628. Mid-infrared excesses consistent with cooling dust
in the ejecta are observed 499-678 days after outburst, and are accompanied by
increasing optical extinction and growing asymmetries in the emission-line
profiles. Radiative-transfer models show that up to 0.02 solar masses of dust
has formed within the ejecta, beginning as early as 250 days after outburst.
These observations show that dust formation in supernova ejecta can be
efficient and that massive-star supernovae can be major dust producers
throughout the history of the Universe.
