Antimicrobial restriction program has been launched from the year 2006. ID physicians previewed the necessity of the antimicrobial agents before the usage. The restricted formula are as followed : 3rd / 4th genenration cephalosporin, carbapenem, fluoroquinolone, glycopeptide, aminoglycoside, and antifungals. The average annual prescription amount was 770,563 DDD (Range 650,225-1,109,740 DDD). The total amount of prescribed antimicrobial agents showed plauteau from year 2009. Third generation cephalosporin (34,531 DDD to 22,772 DDD) and aminoglycoside (4,557 DDD to 2,688 DDD) were less prescribed after introduction of formula restriction. Quinolone class are also less prescribed (25,521 DDD to 9,662 DDD). While, penicillin (4,500 DDD to 34,034 DDD) and first generation cephalosporin (4,166 DDD to 15,194 DDD) were more prescribed after introduction of formula restriction.