Thermal degradation kinetics of chlorophylls  and visual green color loss in  bitter gourd  were investigated at  70, 80, 90 and 100°C. The loss of  visual green color, as represented by the change of  the  –a  value and  the  –a/b  ratio measured by tristimulus colorimeter, All the degradation of chlorophyll a, chlorophyll b as well as visual green color loss  followed  a  first–order reaction.  The rate constants of  all  parameters increased with  increasing temperature  and followed the  Arrhenius model.  The activation energies for chlorophylls a and b were determined as  32.90  ±  2.68 and 49.96  ±  3.86  kJ/mol, while those for  –a value and  –a/b  ratio  were found as  22.75  ±  1.96  and 53.55  ±  4.08 kJ/mol, respectively.