NEW DELHI, May 18 (Reuters) - More legislators charged with crimes will sit in India's new parliament than previously, a democracy watchdog said on Sunday, in a reminder that crime still pays in the world's largest democracy.

Prime minister-elect Narendra Modi, who made fighting graft a central plank of his victorious campaign, won a stunning mandate to govern India by claiming the first clear majority in three decades.

But many of his Bharatiya Janata Party (BJP) colleagues elected to the new parliament faces serious criminal charges. Four out of the nine legislators who face murder cases come from his party.

Thirty-four percent of the winners in India's election have criminal cases pending against them, four percentage points more than in 2009, analysis of the candidates affidavits by the Association for Democratic Reforms found.

Of that, 21 percent were charged with serious crimes such as murder, kidnapping and sexual assault, up from 15 percent in the last election, the group said.

In India, political parties are more likely to field criminals who are able to pay their own way. Election expenses have soared, with as much as $5 billion estimated to have been spent in this election.

Moreover, criminals are often winners, with voters choosing candidates they think will take care of their parochial interests when the state isn't able to, analysts say.

Criminals who have easy access to liquid forms of financing can see politics as a lucrative career.

"Many of these deep-pocketed candidates view the money they must spend on elections ... as a down payment on an investment that offers serious returns," Milan Vaishnav of the Carnegie Endowment for International Peace wrote in a recent commentary.