The country's second-biggest carmaker by sales sold 222,740 vehicles in August, up slightly from 220,529 units a year earlier, the company said in a statement.
Sharp sales declines in China continued to affect monthly results, the company said in a statement, citing political tensions between Seoul and Beijing over the deployment of the Terminal High Altitude Area Defense system in South Korea are affecting its market presence in the neighboring country.
Domestic sales rose 9.7 percent on-year to 41,027 units in August from 37,403. And overseas sales fell 0.8 percent to 181,713 from 183,126 over the same period, it said.
China has banned the sale of group tours to South Korea as part of its retaliations against the THAAD installation. Chinese campaigns against South Korean products also weighed on Kia's sales in the world's largest auto market.
Seoul and Washington have argued THAAD is purely aimed at countering missile threats from North Korea. But Beijing has opposed the system, arguing it could spy on its military.
Affected by the THAAD row, Kia's sales in China plunged 54 percent to 149,672 autos in the January-July period from 326,595 units a year earlier, the company said.
In the January-August period, Kia's sales declined 7.8 percent to 1.76 million autos from 1.91 million last year, the statement said. (Yonhap)