The Interior Ministry on its official Twitter feed said the homemade bomb went off yesterday evening in the al-Diar area on the island of Muharraq, northeast of the capital, Manama.
Authorities are describing the bomb attack as "an act of terror," and say two of the wounded policemen suffered serious injuries but are in stable condition.
There has been an increase in attacks in recent weeks targeting security personnel and government institutions in Bahrain, including some using bombs made with natural gas canisters.