Between 1948 and 1973, the percentage of self-employed persons in nonagricultural industries fell from 12.0 to 6.7 percent, but by 1985, it had risen to 7.5 percent. Given this recent growth in entrepreneurial activity, it is of some importance to obtain as accurate information as possible about the size and composition of the entrepreneurial class and of the businesses they operate. The Bureau of the Census Survey of Income and Program Participation (SIPP) provides an opportunity for obtaining this information. This article reports on some new findings, derived from this survey, relating to businesses and business ownership as distinct from self-employment.