Fewer than one in 15 job adverts mention if there is a workplace pension on offer, the TUC has found.
Pensions can help attract the right staff, the TUC says
The union body examined 1,132 job adverts in national and local press and found that just 69 of them mentioned company pension details.
Many employers, particularly large and medium sized, pay money into a pension scheme for their workers.
The TUC said firms could miss out on attracting good staff by not being clear about pension benefits on offer.
TUC General Secretary Brendan Barber said that employers offering pension schemes "should be boasting about it".
"Those who don't are missing a golden opportunity to attract and retain key workers who are seeking a pension in their benefits package," Brendan Barber, TUC general secretary, said.
"If all job adverts gave clear information on their pension schemes prospective employees would take the advertisement more seriously," he added.
In recent years many firms, have reduced the amount of money they pay into their workers' pensions.
In addition, firms have also been closing their lucrative final salary schemes to new employees.
Final salary pensions offer employees a fixed percentage of their salary when they retire but can be expensive for employers.
Nevertheless, despite the pension cuts and the closing of final salary schemes UK employees still pay billions of pounds each year into their workers' pensions.