This report uses data from the Survey of Income and Program Participation (SIPP) to examine issues related to health insurance coverage. It has two major points of focus. First, it presents quarterly estimates of the extent and type of health insurance coverage (and the characteristics of those who lacked insurance) from the first quarter of 1986 to the fourth quarter of 1988. The sources of this information are interviews from the 1985, 1986, and 1987 SIPP panels. Interviews for the 1985 panel were conducted between February 1985 and August 1987. The comparable dates for the 1986 and 1987 panels were February 1986 to August 1988 and February 1987 to May 1989, respectively. Since SIPP panels overlap, it was possible to combine quarterly estimates from more than one panel. For example, estimates of health insurance coverage for the second through fourth quarters 1986 and the first quarter 1987 are based on estimates combining the 1985 and 1986 SIPP panels. Estimates based on combined panels have lower sampling errors than those based on one panel.