As the work force grays, a small but growing number of job boards catering to the mature worker are emerging on the Internet. The sites are gaining ground as employers realise that they must look outside traditional age ranges to find expertise.

Such websites say they are not trying to exclude younger workers. Rather, the job boards are pinpointing companies that have expressed a commitment to hiring older workers, in an era when some workers can face barriers because of their higher salaries and costlier benefits.

Most of these websites list openings to attract people who are at least 50 to 55 years old, but at least one new entry — jobs4point0.com — is focusing on job seekers who are 40 and over.

Some of the sites certify employers as having a work environment that is suitable for and appealing to older workers. Retirementjobs.com, for example, has certified Borders Group, REI, H&R Block and Robert Half International, among others.

The websites vary greatly in how they operate. Some, like retirementjobs.com or seniors4hire.org, offer positions ranging from executive to clerical. Others are specialised; these include yourencore.com, which leads retired engineers and scientists to companies looking for short-term project assistance.

Of the estimated 76 million baby boomers reaching retirement in the coming years, some will start businesses. But the majority will continue to seek the familiarity and security of a regular paycheck. They want jobs that offer flexibility, with part-time or irregular hours, and these jobs are typically in service industries like retail and fast food or the rapidly expanding medical care field. Those kinds of jobs are well represented on the websites intended for mature workers, who can usually examine the listings free, although they may have to register to find a job’s full details.

During the first week of January, seniorjobbank.com, for example, listed sales and marketing jobs at the Girl Scouts of Central Maryland, at a pay of $8 to $10.10 an hour. There were also some high-paying jobs, like a systems engineer for a military telecommunications firm in Clarksburg, Maryland, with a salary of $85,000 to $110,000.

A recent search on retirementjobs.com for “sales” turned up 180 listings in multiple locations, many from the temporary agency, Manpower. The Bank of America was looking for tellers, and Deloitte & Touche for a variety of jobs, including health care consultants. Salaries were not given.

Usually, the employer pays to list jobs. For example, seniorjobbank.com charges the employer $89 to post a listing for 60 days, whether the position is clerical or executive, full or part-time.

Since early 2005, when W. Eugene Burnard took over the website, as many as 4,000 employers have listed jobs, he said. The site has 7,000 to 9,000 visitors daily. Burnard says older job seekers still face a social bias. “It’s in the very early stages of changing,” he said, “but it’s still a very tough road out there.”

Seniors4hire.org attracts mostly men over 55 who have been laid off or have relocated, said Renee Ward, who founded the site. This site gets 30,000 to 50,000 visitors monthly and has 1,200 registered employers, including Radio Shack, Staples and Bank of America. Mostly full-time jobs are listed, along with about 68,000 job seekers. Companies are charged $65 for a 60-day listing.

Jobs4point0.com only accepts openings directly from companies, said founder Steven J. Greenberg. Job seekers register, search under categories or company names and ask for the details to be sent via e-mail. Companies pay $89 for a 30-day listing.

Richard G. Sobel, 47, who worked as a lawyer at Marsh & McLennan, the huge insurance broker, turned to jobs4point0.com after he was laid off last autumn. He has interviewed for a corporate legal position he discovered through the site, but does not yet know if he got the job. Sobel said he was dismayed to discover that a legal recruiting agency where he was registered had never passed along his name for the position. “The job was a good fit,” he said, “but I never would have heard of it if it hadn’t been for the website.”