Many women use commercially available home pregnancy tests to determine their pregnancy status before seeking professional health care. Despite the increasing popularity of these products, no national estimates have been reported to date on their frequency of use. We analyzed available data from the 1988 National Maternal and Infant Health Survey to determine the frequency of use of home pregnancy tests during recent pregnancies of women of varying sociodemographic backgrounds. Approximately 33 percent (N = 4700) of the women surveyed used such a device. Use was most frequent among women who were white, married, over age 39 years, highly educated, or had a high family income. We conclude that home pregnancy testing appears to be a frequent procedure, especially among women of high socioeconomic background.