This paper aims at evaluating HSDI diesel passenger cars introduction. The result of economic analysis after accounting for the life cycle cost per car shows a saving of 13,836 thousand won in fuel cost per diesel car assuming a life of 10 years and the annual travel distance of 20,000km. Assuming an average travel distance of 20,000km and a 10% increase in sales of diesel passenger car, the social benefit starts to accrue from the year 2002 and, in 2010, is estimated to be 154.1 billion won relative to the gasoline passenger car. The cumulative social benefit up to 2010 under the same assumptions is expected to reach 636.8 billion won.