LOS ANGELES (Reuters) - Radio host Glenn Beck has signed a $100 million deal with syndicator Premiere Networks Inc to continue distributing the conservative pundit's popular program for another five years, a source with knowledge of the deal said on Monday.

Beck and Premiere, a unit of Clear Channel Communications Inc, announced the agreement on Monday, but did not disclose financial details.

The conservative personality had hosted his own television show on the Fox News channel until April last year when he left amid slumping ratings. But his radio program has maintained a loyal following and a growth rate of 50 percent, adding nearly 200 stations in the last five years, according to Premiere.

"The Glenn Beck" program currently airs on 400 stations and is the third most popular radio show in the United States behind those of fellow conservative commentators, Rush Limbaugh and Sean Hannity.

Premiere and Beck's company, Mercury Radio Arts, also extended their deal under which Premiere represents Beck's Web properties - streaming video network GBTV, news and information site TheBlaze.com, e-commerce marketplace Markdown.com and fan portal GlennBeck.com - to advertisers and sponsors.

(Reporting By Bob Tourtellotte; editing by Gunna Dickson)