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Microalgae is a promising source for renewable biofuels, medicines, healthy foods, animal feeds and many more.  Microalgae have to be produced in a large scale in order to give a significant impact for the benefit of the society.  Consequently, an understanding on kinetic growth model of particular microalgae becomes necessary for the purpose of scaling up the production system. This study explores the development of an algae growth model for the Chlorella kessleri culture.  The proposed growth model for Chlorella kessleri was developed from the original Contois growth model, which later modified to include the second substrate as the influencing factor for the growth of cell biomass. Differential equations resulted from mathematical development and modification of Contois model were numerically solved using the Runge-Kutta method. Values of model parameters are optimized using the Levenberg-Marquardt algorithm method.  All computation for the above modelling purpose were done with the aid Matlab 7.1 software. The results of the study show that validation the original Contois model produced predictions of cell and substrate concentrations which deviate from experimental data.  When the Contois model was modified to include the effect of the second substrate for the Chlorella kessleri cell growth, in addition to N-NO₃ as the first substrate, predictions produced excellent agreement with the experimental data.  Further validation against other experimental data of Chlorella kessleri culture is required to allow the generality of the proposed modified Contois model