  We present a preliminary measurement of the branching fraction for B to rho e
nu and of the CKM matrix element |Vub| using approximately 55 million B Bbar
meson pairs collected with the BABAR detector. Using isospin relations for
several modes we find BF(B0 to rho- e+ nu) = (3.39+-0.44+-0.52+-0.60)x10^(-4)
and |Vub| = (3.69+-0.23+-0.27+0.40-0.59)x10^(-3). The quoted errors are
statistical, systematic, and theoretical, respectively. These results are
obtained by using five different form-factor calculations.
