Regression analysis was carried out to explore the effects of almond shell activated carbon (ASAC) as a biosorbent for the uptake of Cr(VI) ions from synthetic waste water. The equilibrium and kinetics models for biosorption were examined to best describe the experimental data of Cr(VI) ions biosorption by ASAC using MatLab. Kinetic models (Pseudo 1^st order and Pseudo 2^nd order) were analyzed by least square method (linear and Non-linear). Two parameters (Langmuir, Freundlich, Temkin, Dubinin–Radushkevich, Hills) and three parameter (Redlich-Peterson, Sips, Toth, Koble-Corrigan and Radhke-Prausnitz) adsorption isotherm models were analyzed by both linear and non-linear least square method to obtain the best fit model. Non- linear regression presented a better fitting of model equations. The kinetics is best described by pseudo 2^nd order model. The equilibrium data of Cr(VI) ion followed the Langmuir, Redlich- Peterson and Radke-Prausnitz isotherm models preferably than the other models.