We measure export participation rates in the U.S. manufacturing sector using a new administrative dataset and compare them to participation rates constructed from the commonly used Census of Manufacturers (CM). Both at the establishment and firm level export participation rates are near 40 percent in the administrative data, almost twice as high as in the CM. The discrepancy appears to result predominantly from under-counting of small exporters in the CM. Our findings call for reconsidering the conventional wisdom that around 20 percent of manufacturing firms export.