Maximum power point tracking (MPPT) is aimed in all photovoltaic (PV) applications. The Constant Voltage (CV) based MPPT technique is considered one of the most commonly-used techniques in PV systems. This paper is aimed at enhancing the performance of the CV technique using PI controller with gains determined by the genetic algorithm (GA). The proposed method has been evaluated by numerical simulation using MATLAB under different atmospheric conditions. For evaluation and comparison analysis, the CV based MPPT technique with PI gains determined by the trial and error (TAE) have been presented. Performance assessment covers time response and MPPT efficiency. The results show performance improvement by fast time response and high MPPT efficiency as compared to the CV technique with gains determined by the TAE.