Legal and General has announced it paid 93.6% of critical illness claims in 2009.
The figure has increased figure every year since 2005, when it was 79%.
Last year's results show that 1.8% of the rejections were for non-disclosure and 4.6% were for not meeting the policy definition.
In total, £152 million was paid out, while the average payment was £70,731, and the average age of claimant was 44.
Cancer, terminal illness, heart attack, stroke and Multiple Sclerosis are the main five reasons for claims.
Bernie Hickman, managing director of protection at L&G, said: "We're in the business of paying claims and that should be the main purpose of any insurance provider.
"We have worked tirelessly to combat non-disclosure and we have succeeded in reducing these declined claims year-on-year.
"If you suffer from an illness or condition that is covered on your policy and you have answered all the questions fully at the time of applying, then we will pay out," he added.
