Existence of solutions for a nonisothermal Allen-Cahn type system is proved by using a semidiscrete spectral Galerkin method together with degree theory and maximum principle. Regularity and uniqueness are obtained in a special situation for domains with dimension up to two and smooth enough data. The present system may model the evolution of solidification or melting processes occurring in certain binary alloys. Copyright © 2012 John Wiley & Sons, Ltd.351213921405Beckermann, C., Diepers, H.J., Steinbach, I., Karma, A., Tong, X., Modeling melt convection in phase-field simulations of solidification (1999) Journal of Computational Physics, 154, pp. 468-496Diepers, H.-J., Beckermann, C., Steinbach, I., Simulation of convection and ripening in a binary alloy mush using the phase-field method (1999) Acta Materialia, 47 (13), pp. 3663-3678. , DOI 10.1016/S1359-6454(99)00239-6Boldrini, J.L., Caretta, B.C., Fernández-Cara, E., Analysis of a two-phase field model for the solidication of an alloy (2009) Journal of Mathematical Analysis and Applications, 357, pp. 25-44Jiang, J., Convergence to equilibrium for a parabolic-hyperbolic phase field model with Cattaneo heat flux law (2008) Journal of Mathematical Analysis and Applications, 341, pp. 149-169Rubio, P.M., Planas, G., Real, J., Asymptotic behaviour of a phase-field model with three coupled equations without uniqueness (2009) Journal of Differential Equations, 246, pp. 4632-4652Rappaz, J., Sheid, J.F., Existence of solutions to a phase-field model for the isothermal solidification process of binary alloy (2000) Mathematical Methods in the Applied Sciences, 23 (6), pp. 491-513Moroşanu, C., Motreanu, D., A generalized phase-field system (1999) Journal of Mathematical Analysis and Applications, 273, pp. 515-540Evans, L.C., (1998) Partial Differential Equations, , American Mathematical Society: ProvidenceLadyẑenskaja, O.A., Solonnikov, V.A., Ural'Ceva, N.N., Linear and quasilinear equations of parabolic type (1995) Translations of Mathematical Monographs, , American Mathematical Society: ProvidenceZheng, S., Nonlinear parabolic equations and hyperbolic-parabolic coupled system (1995) Pitman Monographs & Surveys in Pure & Applied Math, , Longman-Wiley: EssexVaz, C.L.D., Boldrini, J.L., (2011) A Mathematical Analysis of A Non-isothermal Allen-Cahn Type System: Error Estimates, , pre-print, accepted for publication in the Mathematical Methods in the Applied SciencesFeng, X., Prohl, A., Numerical analysis of the Allen-Cahn equation and approximation for mean curvature flows (2003) Numerische Mathematik, 94 (1), pp. 33-65. , DOI 10.1007/s00211-002-0413-1Deimling, K., (1984) Nonlinear Functional Analysis, , Springer-Verlag: BerlinLions, J.L., (1987) Control of Distributed Singular Systems, , John Wiley & Sons Inc: New YorkHenry, D., Geometric theory of semilinear parabolic equations (1981) Lecture Notes in Mathematics, 840. , Springer-Verlag: Berlin