The present invention provides sustained-release preparations from which a pharmacologically active substance can be released over a long time and a process for producing the same. Such a sustained-release preparation is produced by melt-granulating a low-melting-point substance and a pharmacologically active substance and melt-coating the surface of the thus obtained particles with (1) a fine powder of a water-insoluble polymer or (2) a fine powder of a water-insoluble polymer and at least one member selected from the group consisting of talc, magnesium stearate and titanium oxide.