Abstract: With the growth of using World Wide Web (WWW), WWW has become a powerful means of dissemination information to the popular. Thus, the demand for faster, more efficient, and more convenient ways for accessing to WWW are urgently required. Consequently, the heterogeneous I/O client devices, i.e., DTMF telephone sets, fax machines, pocket PCs, cellular phones, note books, desktop computers, are devised to allow users to access to WWW. In order to provide suitable WWW access interfaces, currently, many mark-up languages and systems are proposed for these heterogeneous I/O client devices. As a result, n heterogeneous I/O devices need n mark-up languages and systems using this approach. In this paper, we proposed a mark-up language, called Quality of Information Mark-up Language (QIML), and browsing systems to resolve the above problem. With QIML, one can provide suitable and flexible content to heterogeneous client devices, including computers, cellular phones, traditional DTMF telephone sets, and fax machines, using one mark-up language and system. In this way, the overhead for maintaining many web servers for servicing users with heterogeneous I/O client devices can be reduced a lot.