Ganciclovir　(GCV)　is　only　slightly　soluble　in　water　and　hence　oral　GCV　gives　low　absolute　bioavailability.　Liquid　precipitation　is　an　effective　way　to　prepare　micro-sized　drug　particles.　The　solubility　of　GCV　in　several　solvents　or　in　aqueous　solution　at　different　pH　values　was　determined.　According　to　its　solubility　behavior,　reactive　precipitation　was　suggested　as　the　micronization　method　of　GCV.　The　mean　particle　diameter　of　micronized　GCV　powder　was　around　15∼20　μm,　smaller　than　that　of　raw　GCV　powder,　and　the　size　distribution　of　micronized　GCV　was　narrower　than　that　of　raw　GCV.　The　stirring　rate,　the　type　and　addition　of　stabilizing　agents　seemed　to　have　no　significant　effect　on　the　particle　size　of　micronized　GCV.　Micronized　GCV　showed　much　faster　dissolution　rate　than　raw　GCV.