Aviva paid more than £439m to its life and critical illness (CI) customers in 2011, a total of 99%, making payments for 10,495 life claims and 1,568 CI claims.
This breaks down as 99.7% of life insurance claims, and 94.1% of critical illness claims.
This figure includes £320 million paid to the families of life insurance customers who have died or been diagnosed with a terminal illness, and nearly £114 million paid to customers with critical illness (CI) cover.
Overall 0.4% of claims were declined due to non-disclosure. This breaks down as 0.3% of life insurance claims, and 1% of critical illness claims.
Cancer remains the most common cause of critical illness claims at 67%, followed by heart attack (10%), stroke (7%), multiple sclerosis (6%) and benign brain tumour (2%).
Commenting, Robert Morrison, chief underwriter for Aviva, said: "We know all too well how financial security can make a huge difference at a distressing time, so we make it our business to pay as many claims as we possibly can.
"We're extremely proud of our claims record at Aviva. We are constantly working to make our customer journey as simple and straightforward as possible.
"We're striving to ensure that whether they're taking out cover or making a claim, our customers have exactly the experience they would want at that time."