Nimonic 80A is a nickel-chrome superalloy, commonly used due to its high resistance against creep, oxidation, and temperature corrosion. This paper presents the material constitutive models of Nimonic 80A superalloy. Johnson-Cook (JC) and modified JC model is preferred among the different material constitutive equations (Zerill Armstrong, Bodner Partom, Arrhenius type) due to its accuracy in the literature. Three different types of compression tests were applied to determine the equation parameters. Firstly, quasi-static tests were performed at room temperature. These tests were conducted at 10(-3), 10(-2), and 10(-1) s(-1) strain rates. Secondly, compression tests were performed at room temperature at high strain rates (370-954 s(-1)) using the Split-Hopkinson pressure bar. Finally, compression tests were performed at a temperature level from 24 to 200 degrees C at the reference strain rate (10(-3) s(-1)). Johnson-Cook and modified JC model parameters of Nimonic 80A were determined with the data obtained from these tests, and they were finally verified statistically.