Upflow anaerobic sludge blanket reactor (UASB) performance is influenced by change in the hydraulic and organic load. Aim of this study was to evaluate the performance for a 4.14L reactor controlling temperature (30 O 1°C) with a jacket circulation and a thermostat bath. Sludge age and kinetic coefficients were calculated. 500 mg/L of glucose as volumetric organic load were tested for different loading from 0,50 to 3.0 kgCOD/m3d kgCOD/m3d. Theoretical hydraulic retention time assayed from 24 to 4 hours, keeping a constant flow rate with a peristaltic pump. Sludge age recommended was 165 days and it was found enough to achieve a COD reduction by 86.87%. Rate constants found were: decay coefficient endogenous (Kd) = 0.0023 d”“1, yield coefficient cell (Y) = 0.0767 KgSSV/KgDQOr, maximum rate of substrate utilization per unit of microorganisms, (k) = 0.2578 mgDQO/mgSSV.d, substrate saturation constant (Ks) = 214 mg/L and maximum specific growth rate (I¼max) = 0.0198 d”“1. Equation found by linear regression was able to predict the an operation of the reactor with a standard error of 1.882% in terms of COD´s efficiency. Rate coefficients proposed by the process was developed successfully.