Opinion polls indicate that over 40 percent of Americans attend worship services each week. However, attendance counts in several North American counties and Roman Catholic dioceses suggest that worship attendance may be much lower. In this article a new measurement strategy is used to estimate total weekly worship attendance. First, using a variety of resources we develop an estimate of the total number of religious congregations in the United States by religious family. Contrary to many published sources, the total number of congregations is estimated at just over 330,000. Second, using known population values and sample-based attendance counts we develop estimates of average weekly worship attendance for religious congregations by religious family. The resulting totals suggest that fewer than 22 percent of Americans attend worship services each week. This lower level of attendance provides further evidence that Americans tend to overreport worship participation and are less religiously active than the polls show.