The US Congress has approved nuclear trade with India.
Final approval came late on Wednesday when the Senate voted 86-13 to ratify the agreement, sending the legislation to President George Bush to sign into law.
The vote ended a three-decade ban on US nuclear trade with India.
President Bush says it will strengthen global nuclear non-proliferation efforts.
According to the Confederation of Indian Industry, the deal could mean $US27 billion in investment in 18-20 nuclear plants in India over the next 15 years.
US Secretary of State Condoleezza Rice is due to make a trip to India this weekend.
France announced on Tuesday it had signed a nuclear cooperation agreement with India and Russia is building two 1,000-megawatt reactors in the southern Indian state of Tamil Nadu.
India detonated a nuclear device in 1974 and last tested in 1998.
Pakistan wants deal
Pakistan is also demanding a civilian nuclear agreement with the United States.
Prime Minister Yousuf Raza Gilani says the US can't discriminate and will have to accommodate a key ally in its "war on terror".
Pakistan has opposed the US - India deal, warning that approving it could lead to a regional nuclear arms race.
The US deal allows India access to US civilian nuclear technology and fuel in return for inspections of its civilian - but not military, nuclear facilities.
Pakistan became a nuclear power in 1998 after testing devices in response to underground tests done by India.
However, Washington has already indicated that Pakistan's track record of nuclear proliferation disqualifies it from such an arrangement.
In 2004, top Pakistani nuclear scientist AQ Khan admitted to passing on nuclear secrets to Libya, Iran and North Korea. He retracted his confession in 2008.