Avinadav was one of the sons of King Shaul, the first king of Israel. Hebrew Wikipedia gives his mother as Achinoam, daughter of Achimaatz, Shaul's wife. The genealogy in Chronicles lists him among Shaul's sons: "Shaul begot Yehonatan, Malkishua, Avinadav and Eshbaal." The Book of Samuel also mentions another Avinadav, a brother of King David, who should not be confused with him.

In the war against the Philistines, Avinadav fought alongside his father and brothers on Mount Gilboa. The Philistines pursued Shaul and his sons and struck down Yehonatan, Avinadav and Malkishua, the sons of Shaul. Badly wounded by the archers, Shaul fell on his sword; the text concludes that Shaul, his three sons and his arms-bearer died together that day.

The next day the Philistines found Shaul and his three sons lying on Mount Gilboa and hung their bodies on the wall of Beit She'an. When the men of Yavesh-Gilead heard of it, their valiant men marched all night, took down the bodies of Shaul and his sons, brought them to Yavesh and burned them there, then buried their bones under the tamarisk in Yavesh and fasted seven days.

Later, King David had the bones of Shaul and his son Yehonatan brought from Yavesh-Gilead to the tomb of Kish, Shaul's father, at Tzela in the land of Binyamin; the Hebrew text does not explicitly mention Avinadav's bones in that transfer.