Christian Solidarity Worldwide (CSW) says more than 600 acts of violence against religious minorities, including Christians, have happened since May this year.
It also says victims of communal attacks aren't receiving justice or compensation.
India's prime minister, Nahendra Modi, arrives in the US today for four days, and will be seeing President Barack Obama as well as addressing the United Nations General Assembly.
CSW's Chief Executive, Mervyn Thomas, said: "CSW is urging the US government to raise the issue of widespread hate campaigns by state and non-state actors against religious minorities in talks with Prime Minister Modi, and to insist that justice is done for the victim-survivors of violence against religious minorities."
"We are encouraging our US-based supporters to email their representative in Congress in order to encourage them to discuss the concerns of India's religious minorities with the prime minister."
In 2008, around 100 Christians were killed in attacks in the Indian state of Odisha, formally known as Orissa.