Album phòng thu

• 1999: Sorrow (Vol. 1)
• 2000: Rouge (Vol. 2)
• 2001: Tres (Vol. 3)
• 2003: Smile (Vol. 4)
• 2006: Smile Again (Vol. 5)
• 2007: The Sixth Miracle (Vol. 6)
• 2008: Sensibility (Vol. 7)
• 2011: Pitta (Vol. 8)

Mini album

• 2009: EGO
• 2012: Good Boy

Album tái phát hành

• 2000: Volume 1 & 2 Repackage

Album phiên bản đặc biệt

• 2006: Thank You I Can Smile Again

Album hay nhất & trực tiếp

• 2001: Live Concert (Album trực tiếp)
• 2002: Best & Live New Release (Album hay nhất & trực tiếp)
• 2003: Ultimate Edition (Album hay nhất)
• 2010: Timeless; The Best (Album hay nhất)
• 2013: Flash Back (OST Album hay nhất)

EP kỹ thuật số

• 2006: "Love Is Beautiful"
• 2006: "Tomorrow" (도전성공시대 '내일은 모델퀸')
• 2007: "Crush" (với Jade from Sweetbox)
• 2007: No.1 Hitz: The Biggest Hits From Today's Supersta
• 2008: "Love Is...Lalala" (với Yuri)
• 2008: "Gypsy Tears"
• 2009: "Love Is Not a Crime" ("사랑이 죄인가요") (Ja Myung Go OST)
• 2009: "Don't Forget" ("잊지 말아요") (IRIS OST)
• 2010: "That Woman" ("그 여자") (Secret Garden OST)
• 2011: "Again, I Love You Today" ("오늘도 사랑해") (The Princess' Man OST)
• 2011: "I Can't Drink" ("아이캔’t 드링크") (The Greatest Love OST)
• 2012: "It Hurts Here" ("여기가 아파") (A Thousand Days' Promise OST)
• 2012: "After a Long Time" ("한참 지나서") (Hoàng tử gác mái OST)
• 2012: "Love and Love" ("사랑아 또 사랑아") (Arang Sử đạo truyện OST)
• 2013: "Spring Rain" ("봄비") (Gu Family Book OST)
• 2013: "I'm Just Crying" ("울고만있어") (Good Doctor OST)
• 2014: "Fervor" ("불꽃") (The Fatal Encounter OST)