Charmless Hadronic B Decays at BaBar

Using 22.7M B events collected with the BABAR detector at SLAC, we present preliminary measurements of the branching fractions for charmless hadronic decays of B mesons into two-body, quasi two-body and three-body final states with pions, kaons, and ρ and a0 resonances. In the search for exclusive B0 → π+π-π0, they measure Β(B0 → ρ±(770)π±) = (28.9 ± 5.4 ± 4.3) x 10-6, together with the relative asymmetry Αphys = -0.04 ± 0.18 ± 0.02. They also set the upper limits on B0 → ρ0(770)π0, non-resonant B0 → π+π-π0, B0 → a0± (→ ηπ±)π-= and B0 → K0(bar K)0