Year 545 (DXLV) was a common year starting on Sunday of the Julian calendar. The denomination 545 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.

• Emperor Justinian I sends Narses, Byzantine general, to the rulers of the Heruli, to recruit troops for the campaigns in Italy and Syria.^[1]

• Gothic War: King Totila establishes his military base at Tivoli (Central Italy), and prepares a campaign to reconquer the region of Latium.
• The monastery of Clonmacnoise is founded in Ireland by Ciarán Mac a tSaor on the River Shannon (approximate date).

• Yangwon becomes ruler of the Korean kingdom of Goguryeo.^[2]

• King Khosrau I signs a five year truce with the Byzantine Empire, but war continues to ravage the Caucasus region, especially in Armenia.

• The Synod of Brefi is held at Llanddewi Brefi, to condemn the Pelagian heresy. Dubricius, archbishop of South Wales, resigns his position in favour of David (approximate date).

• Abd Allah ibn Abd al Muttalib, father of Muhammad (d. 570)
• Fei Di, emperor of Northern Qi (d. 561)
• Peter, Byzantine general (d. 602)

• June 3 – Clotilde, Christian wife of Clovis I and ancestress of the succeeding Merovingian dynasty (b.474)
• October 12 – Mobhí Clárainech, Irish abbot and saint
• Stotzas, Byzantine rebel leader
• Approximate date
  • Budic II, king of Brittany
  • Laurence, bishop of Sipontum
  • Medardus, bishop of Vermandois