  The decay width and the mass of the D_s1(2536) have been measured via the
decay channel D_s1 -> D*+K_S using 232 fb^-1 of data collected with the BABAR
detector at the PEP-II asymmetric-energy e+e- storage ring. The result for the
decay width is (1.03 +- 0.05 +- 0.12) MeV/c^2, with the first error denoting
the statistical uncertainty and the second one the systematic uncertainty. For
the mass, a value of (2534.85 +- 0.02 +- 0.40) MeV/c^2 has been obtained. The
systematic error is dominated by the uncertainty on the D*+ mass. The mass
difference between the D_s1 and D*+ has been measured to be (524.85 +- 0.02 +-
0.04) MeV/c^2.
