Ctrip.com International Ltd and Qunar.com Inc, the two Chinese main tourism websites, which have been rivals for years, agreed to cooperate on Monday in order to enlarge their market share.

Ctrip.com, the largest online travel agency in China, became a vacation products supplier for Qunar.com, the Chinese leading travel search engine, whose largest shareholder is Baidu Inc.

"Travelers will be able to find all Ctrip.com's vacation products on Qunar.com in the future," said Peng Xiaomei, deputy president of Qunar.com.