[en] We obtain the effective potential at finite temperature within the left-right-symmetric model. We take the Higgs sector to consist of two doublets, and calculate its finite-temperature effective potential up to the order of ''ring diagrams,'' using analogous techniques to those employed in the derivation of the effective potential in the standard model. We find that two first-order phase transitions can exist: one at the SU(2)_R-breaking scale, the other at the usual SU(2)_L direct-product U(1)_Y-breaking scale. Even though more parameters are present than in the standard model, we find that the electroweak phase transition is still too weak to allow baryon asymmetry to survive the transition, if the lower bound of the Higgs boson mass from experiment is adhered to