Using Current Population Survey (CPS) microdata, I examine trends and the causes of the trends from 1979 to 1998 in business ownership among several ethnic/racial groups in the United States. I find rapid growth rates for the number of self-employed blacks, Hispanics, Asians and Native Americans relative to whites over the past decade or two. I find that the rapid growth rates were primarily due to expansions in the labor force for these groups. With the exception of female rates in the 1980s, trends in business ownership rates were fairly flat over the past two decades. There were, however, important differences across groups in changes in self-employment rates over the past decade or two. I use a dynamic decomposition technique to explore the causes of these differential trends and find some interesting patterns. For example, I find that increasing levels of education and relative declines in the age distribution of the workforce for some minority groups contributed to increasing racial gaps in self-employment.