The thermodynamic parameters for the extraction of Am3+with pyrazolones (HA=HPMBP or HPMTFP) alone as well as their mixtures with one of the crown ethers B15C5 or DCH18C6 have been calculated In chloroform at 30°C using temperature coefficient method. The self-adduct species AM(A)3HA is enthalpy stabilized. The adduct species AM(A)3HA DCH18C6 are stabilized by entropy and opposed by enthalpy. The adduct species AM (A)3HA B15C5 (HA=HPMBP) and Am(A)3.B15C5 or Am(A)32B15C5 (HA=HPMTFP) are stabilized by enthalpy. These data have been correlated with the difference In the nature of binding of the two crown ethers with Am3+.