UMC Revised 4Q08 Guidance and Reports Sales for November 2008

Taipei, R.O.C. -December 9, 2008 - United Microelectronics Corporation (NYSE: UMC; TAIEX: 2303), (UMC) today revised downward its 4Q08 guidance and reported unaudited net sales for the month of November 2008.

Due to weak semiconductor demand resulting from the global economic recession and wafer shipments being pushed-out, UMC announces that it has revised downward its fourth quarter 2008 guidance, originally disclosed on October 29th, 2008. UMC now expects its fourth-quarter revenue to be between NT$18.2 billion and NT$18.7 billion, with 4Q 2008 gross profit margin to be between 7% and 9%. UMC maintains that profits from operations will be positive for overall 2008.

(*) All figures in thousands of New Taiwan Dollars (NT$), except for percentages.

Additional information about UMC is available on the web at http://www.umc.com.