Year 993 (CMXCIII) was a common year starting on Sunday (link will display the full calendar) of the Julian calendar.

• Spring – The 12-year-old King Otto III gives the Sword of Saints Cosmas and Damian (also known as the Sword of Essen) as a gift to the convent in Essen. It symbolises the martyrdom of Cosmas and Damian, the patron saints of the city.
• Charles, duke of Lower Lorraine, dies in prison in Orléans (see 991). He is succeeded by his son Otto II, who inherits the full dukedom and pledges his allegiance to Otto III.

• July 4 – Pope John XV issues a decree canonizing the late Bishop Ulrich of Augsburg, the first recorded canonization of a saint.

• An increase in ¹⁴
  C concentration, recorded in tree rings, as well as ³⁶
  Cl and ¹⁰
  Be isotopes, recorded in ice cores, suggests that a strong solar storm may have hit the Earth in either 993 or 994.^{[1][dubious – discuss]}

• Majd al-Dawla, Buyid emir of Rayy (d. 1029)
• Samuel ibn Naghrillah, Spanish Talmudic scholar
• Sultan al-Dawla, Buyid emir of Fars (d. 1024)

• March 13 – Odo I, German nobleman
• October 19 – Conrad I, king of Burgundy
• December 9 – Egbert, archbishop of Trier
• Arnulf (or Aernout), count of Friesland
• Borrell II, count of Barcelona and Urgell
• Charles, duke of Lower Lorraine (b. 953)
• David II, prince of Tao-Klarjeti (Georgia)
• Landenulf II, Lombard prince of Capua
• Maelcairearda, king of Uí Briúin (Ireland)
• Minamoto no Masanobu, Japanese nobleman (b. 920)
• William I, French nobleman (b. 950)