The men's 4 × 400 metres relay event at the 1948 Olympic Games took place on 6 and 7 August.

The United States team won the final with a time of 3:10.4.

[1] Prior to the competition, the existing World and Olympic records were as follows.

All times are British Summer Time (UTC+1) The first two teams in each heat qualified for the Final.

[2] Heat 1 Heat 2 Heat 3 Key: DNF = Did not finish