The 1970 All-Ireland Under-21 Hurling Championship was the 7th staging of the All-Ireland Under-21 Hurling Championship since its establishment by the Gaelic Athletic Association in 1964.
Cork entered the championship as the defending champions.
On 1 November 1970, Cork won the championship following a 5-17 to 0-8 defeat of Wexford in a replay of the All-Ireland final. This was their 4th All-Ireland title in the grade and their third in succession.
Wexford's Mick Butler was the championship's top scorer with 6-30.
In keeping with their senior and minor teams, Galway's under-21 hurlers left the Munster Championship where they had been playing since 1964. Having no competition in their own province, Galway received a bye to the All-Ireland semi-final stage.
Quarter-finals
Semi-finals
Final
First round
Semi-finals
Final
Final
Semi-finals
Finals