In the second quarter ended June 30, the company's core income fell to $625 million, or $2.57 per share, from $879 million, or $3.45 per share, the previous year.
According to Refinitiv IBES data, analysts expected a profit of $1.97 per share on average.
In premarket trading, the company's stock was down 1.1 percent.
Travelers, based in New York, is often regarded as a bellwether for the insurance industry because it typically reports ahead of its peers. Its net written premiums increased 11 percent to $9.02 billion in the third quarter.
Swiss Re forecasted this month that global insurance premiums will exceed $7 trillion for the first time ever by the end of this year.