Chiral phase transition in effective models of QCD

Incorporating its most relevant global symmetry, chiral effective models are aimed at investigating, in a simplified framework, important aspects of the yet unsolved QCD. We review some recent results obtained in these models on the restoration of chiral and axial symmetries, on the boundary of the first order phase transition region in the m_pi-m_K-plane at vanishing baryonic chemical potential mu_B,and on the mu_B-T phase diagram.