Year 4 BC was a common year starting on Tuesday or Wednesday (link will display the full calendar) of the Julian calendar (the sources differ, see leap year error for further information) and a common year starting on Monday of the Proleptic Julian calendar. At the time, it was known as the Year of the Consulship of Sabinus and Rufus (or, less frequently, year 750 Ab urbe condita). The denomination 4 BC 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.

• March 13 – Lunar eclipse
• June 26 – Augustus adopts Agrippa Postumus and Tiberius, who in turn adopts Germanicus.^[1]
• Upon the death of Herod the Great, there is unrest in his client kingdom of Judea. His son, Herod Archelaus, becomes the new ruler. Herod Antipas becomes tetrarch of Galilee and Perea. The governor of Syria, Publius Quinctilius Varus, marches down to Jerusalem from Antioch to restore order; around 3000 jews are crucified.^[2]
• Namhae becomes king of the Korean kingdom of Silla.^[3]

• Approximate date – Seneca the Younger, Córdoban-born Roman Stoic philosopher, statesman and dramatist (d. AD 65)

• March or April – Herod the Great, king of Judea (b. 73 BC);^[4] some authors date his death to 1 BC (see Date of Herod's death).
• Antipater, Jewish heir and son of Herod the Great
• Malthace, Jewish woman and wife of Herod the Great
• Marcus Porcius Latro, Roman rhetorician
• Marcus Tullius Tiro, Roman writer, freedman of Cicero