Seoul's Finance Ministry says the foreign ministers of South Korea and Vietnam signed a revised agreement to prevent double taxation on the occasion of bilateral summit talks last week.
The original pact on preventing double taxation went into effect in 1994.
The latest revision seeks to improve the investment environment for South Koreans firms entering the Vietnamese market.
It includes lowering the tax rate on income generated by copyright and trademarks from 15 to ten percent.
The ministry also said that Foreign Minister Kang Kyung-wha signed a similar agreement with her Cambodian counterpart Prak Sokhonn during their meeting in Busan last week.