The 1900 Federal Census of the United States did not ask currently-married women whether they had been married previously. This note uses the direct report on remarriage in the 1910 census to evaluate the performance of the “own-child checks” that several researchers have used with the 1900 census to substitute for direct information on remarriage. Accurate information on remarriage status is important for fertility and mortality estimation methods that rely on marital duration. The checks detect fewer than two-thirds of wives who report they are remarried. The use of these checks, however, does not introduce large amounts of error in an analysis of either fertility or mortality. The checks work better for white women than for black women. nt]mis|For comments we thank Paul David, Samuel Preston, Warren Sanderson, James Trussell, and seminar participants at the Office of Population Research, Princeton University. Two anonymous referees made detailed suggestions that substantially improved the paper. Address all correspondence to T.W. Guinnane.