Studies were conducted on ripening characteristics of prosciutto during manufacturing. Prosciutto was manufactured by curing with spice mix. It was cured at 5℃ for 1 month followed by holding at al℃±1℃ for 1 month and then ripened for 4 months at 27℃±1℃ and RH 65-90%. The pH increased from 5,7 to 6.2 during ripening. Salt content also increased as moisture decreased. Free amino nitrogen (NH₂-N) increased sharply during the first month of ripening, then changed to 68.2 ㎎% at the end of ripening. Residual nitrate (NO₃^-) and nitrite (NO₂^-) were rapidly depleted within the first month of ripening. At the end of ripening they were 20.4 ppm and 4.5 ppm, respectively. Microbial counts increased remarkably until the first months of ripening, then decreased slowly. At this time total bacteria count and lactic acid bacteria were 2.1 × 10^7 and 2.2 × 10^6 cells/g, respectively. Almost all of ATP, AMP, IMP and Inosine tended to degrade rapidly during the initial manufacturing period. But as much as 0.8-3.5 μmole/g of ADP remained during manufacturing. Mypoxanthine was accumulated to 5.3 μmole/g at the first month of ripening, then degraded slowly.