In this work we have studied the properties of CdS films obtained by the chemical bath deposition technique. We studied the influence of pH control of the reaction solution on the structural and optical properties of chemically deposited CdS films. For this, we deposited two sets of CdS films on glass substrates using two different reaction solutions. The main difference between the solutions was that one included the use of a pH-10 NH4OH/NH4Cl controller solution or buffer, which produces a more uniform pH of the reaction solution during the film-growth process. Using each reaction solution, five CdS films were deposited at 80 °C, varying the deposition time from 15 to 120 minutes. The structural and optical properties of both sets of films were determined by X-ray diffraction and by absorption, transmission and reflection spectroscopy. The differences in the properties of the films were analyzed in terms of pH control.