The analytical solution presented by Sudicky and Frind <1984> for the problem of transport of a two-member decay chain through a single fracture in a porous rock matrix for the general case was correct. However, when this analytical solution was applied to several examples, a mistake was made in its evaluation, and all the results are incorrect. In particular, the surprising effect identified <Sudicky and Frind, 1984, p. 1028> the second member of the decay chain can penetrate further along the fracture than the first, even though the diffusion coefficients and the retardation factors are the same for both species is an artifact. In this paper the errors of Sudicky and Frind are identified, and a simple analytical solution is derived for the particular case in which both members of the chain have the same retardation and diffusion properties. This simple analytical solution has been applied to their examples, and results show that for a decay chain of two radionuclides with the same retardation and sorption properties, if a pulse of the parent radionuclide is injected into a single fracture, the ratio of concentrations of the two members of the chain at any point along the fracture or into the matrix is equal to the ratio of total masses of both radionuclides in the system. ¿ 2000 American Geophysical Union