The low-temperature specific heat C(H) of several rare-earth manganites (La 0 . 7 Sr 0 . 3 MnO 3 , Nd 0 . 5 Sr 0 . 5 MnO 3 , Pr 0 . 5 Sr 0 . 5 MnO 3 , La 0 . 6 7 Ca 0 . 3 3 MnO 3 , La 0 . 5 Ca 0 . 5 MnO 3 , La 0 . 4 5 Ca 0 . 5 5 MnO 3 and La 0 . 3 3 Ca 0 . 6 7 MnO 3 ) was measured as a function of magnetic field. We observed behavior consistent with thermodynamic expectations, i.e., C(H) decreases with field for ferromagnetic metallic compounds by an amount which is in quantitative agreement with spin-wave theory. We also find that C(H) increases with field in most compounds with a charge-ordered antiferromagnetic ground state. In compounds which show evidence of a coexistence of ferromagnetic metallic and antiferromagnetic charge-ordered states, C(H) displays some unusual non-equilibrium effects presumably associated with the phase-separation of the two states. We also observe a large anomalous low-temperature specific heat at the doping-induced metal-insulator transition (at x=0.50) in La 1 - x Ca x MnO 3 .