This paper introduces a method for estimating the size of the Korean American population in communities in the United States. Since about 22 percent of Korean Americans have the surname Kim and the telephone subscription/listing rate for Korean Americans is extremely high, a fairly simple equation for such estimation can be constructed. The number of Kims listed in the published telephone directory for a community, the mean size of the Kim households, the residence telephone subscription! listing rate, and the proportion of Kims are the factors included in the equation. A specific value for each of the factors has been derived from various “unobtrusive” and nongovernmental sources. Only insignificant differences have been found between estimates made using this method and the enumeration figures from the 1980 census for the Korean American population in the New York metropolitan area and Los Angeles and Orange counties. It appears that the equation is effective in estimating the size of the Korean American population in a community and could be a useful instrument in evaluating the accuracy of the 1980 Census enumeration of Korean Americans. The paper also describes the potential utility of Kims listed in published telephone directories as a sampling frame of Korean Americans in the United States. The ideas and procedures presented here can be extended to other ethnic populations with unique surnames, such as Nguyen for the Vietnamese American population and those starting with “Yama” ... for the Japanese American population.