National Interstate Named Forbes 100 Most Trustworthy Small-Cap Company

RICHFIELD, Ohio, April 22, 2010 (GLOBE NEWSWIRE) -- National Interstate
Corporation (Nasdaq:NATL) today announced that it has been chosen as the most
trusted small-cap company on the Forbes 2010 Most Trustworthy Companies list.
The Forbes list recognizes companies that consistently demonstrated transparent
and conservative accounting practices and solid corporate governance and
management.

To create the list, over 8,000 companies traded on the U.S. exchanges were
evaluated, receiving an accounting and governance risk score. National
Interstate was named the top small-cap company, and was also one of only three
companies to receive a maximum score of 100.

"We are extremely pleased to be recognized by Forbes as one of the most
trustworthy companies in the country," said Dave Michelson, President and Chief
Executive Officer of National Interstate. "Integrity has always been one of our
core values, and one we commit to in all aspects of our business. We not only
take pride in this ranking, but also believe it is important to our current and
prospective customers. This designation confirms the highly ethical business
practices we have demonstrated since our company was founded."

To view the April 5, 2010 article, please visit www.forbes.com.

About National Interstate Corporation

National Interstate Corporation (Nasdaq:NATL), founded in 1989, is a specialty
property and casualty insurance holding company with a niche orientation and
focus on the transportation industry. We differentiate ourselves by offering
insurance products and services designed to meet the unique needs of targeted
insurance buyers. Our products include insurance for transportation companies,
alternative risk transfer, or captive insurance programs for commercial risks,
specialty personal lines consisting of insurance products focused primarily on
recreational vehicle owners and small commercial vehicle accounts, and
transportation and general commercial insurance in Hawaii and Alaska. We offer
our insurance products through multiple distribution channels including
independent agents and brokers, affiliated agencies and agent Internet
initiatives. Our insurance subsidiaries are rated "A" (Excellent) by A.M. Best
Company. Headquartered in Richfield, Ohio, National Interstate is an
independently operated subsidiary of Great American Insurance Company, a
property-casualty subsidiary of American Financial Group, Inc. (NYSE:AFG)
(Nasdaq:AFG).

CONTACT: National Interstate Corporation
Tanya Inama
877-837-0339
investorrelations@nationalinterstate.com
www.natl.com