This study was performed to determine the time effect on optical properties of solgel-derived Cu(In, Ga)Se-2 (CIGS) thin films at the specific environmental conditions. For this purpose, solgel-derived CIGS thin films were exposed to a variety of environmental conditions at different steps of the production process from the preparation of solution to deposition of substrate. The optical properties of the CIGS thin films changed with the rise of time at the specific environmental conditions such as the increase of the aging time of solgel solution (from 18 to 35 days) and the rise of the annealing time of the thin film (from 15 to 60 min). The CIGS solution was aged with the rise of time to investigate the effect of the aging time on optical properties of the thin film. The films were deposited by aged colloidal solution which kept at -5 degrees C in a dark environment in order to extend the useful life of solution. The color of the colloidal solution changed slightly with the increase in the elapsed time after the preparation of the solution. The increase of the annealing time has affected the optical behaviors of the CIGS thin films with the changes of the surface morphology.