During Thursday night's live televised leaders debate the MEP claimed 60% of the 7000 people diagnosed with HIV in Britain every year are not UK nationals.
He said: "You can come into Britain, from anywhere in the world, get diagnosed with HIV and get the retro-viral drugs which cost up to £25,000 per year, per patient.
"We need to put the National Health Service there for British people and families."
When challenged by Sky News if it was a Christian thing to say he replied: "What good Christian would say to an 85-year-old woman you can't have breast cancer treatment because we can't afford it, whilst at the same time shovelling billions of pounds on foreign aid, allowing people from all over the world to fly into Britain as health tourists to get a HIV test and drugs over £20,000 a year?
"It is a sensible Christian thing to look after your family and your own community first."
The UKIP leader also said he was a 'lapsed Anglican' but did believe in God.
He said he rarely attends church, though: "I think there are millions like me, millions brought up to be Christian, who perhaps in adult life have rather put it at the back of their minds."
When asked if he thought he would ever go to church more regularly he said it was too close to the election to have theological discussions.
Mr Farage added that the UK was still a Christians country: "Well that is perfectly clear, we have a Judeo-Christian culture, we even have a Judeo-Christian constitution - the role of the monarch and the way the whole country is set up.
"That doesn't mean we are not the most tolerant country in Europe in terms of all cultures and other religions we always have been but we mustn't forget who we are."