|Millennium:||1st millennium BC|
|298 BC by topic|
|Gregorian calendar||298 BC|
|Ab urbe condita||456|
|Ancient Egypt era||XXXIII dynasty, 26|
|- Pharaoh||Ptolemy I Soter, 26|
|Ancient Greek era||120th Olympiad, year 3|
|Balinese saka calendar||N/A|
|Chinese calendar||壬戌年 (Water Dog)|
2399 or 2339
— to —
癸亥年 (Water Pig)
2400 or 2340
|Coptic calendar||−581 – −580|
|Ethiopian calendar||−305 – −304|
|- Vikram Samvat||−241 – −240|
|- Shaka Samvat||N/A|
|- Kali Yuga||2803–2804|
|Iranian calendar||919 BP – 918 BP|
|Islamic calendar||947 BH – 946 BH|
|Minguo calendar||2209 before ROC|
|Seleucid era||14/15 AG|
|Thai solar calendar||245–246|
−171 or −552 or −1324
— to —
−170 or −551 or −1323
Year 298 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Barbatus and Centumalus (or, less frequently, year 456 Ab urbe condita). The denomination 298 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.
- The Samnites defeat the Romans under Lucius Cornelius Scipio Barbatus in the Battle of Camerinum, the first battle of the Third Samnite War.
- The Roman armies penetrate into the heart of the Samnite territory and then capture the Samnite cities of Taurasia, Bovianum Vetus and Aufidena.
- Agathocles, king of Syracuse, assists the Italian Greeks against the Bruttians and supported the Greeks against the Romans.
- Ptolemy gives his stepdaughter Theoxena in marriage to Agathocles, the tyrant of Syracuse (in south-eastern Sicily).
- Ptolemy finally brings the rebellious region of Cyrene under his control. He places the region under the rule of his stepson Magas.