Polycrystalline films of CdxPb1-xS (0 ≤ x ≤ 0.05) substitutional solid solutions with a cubic structure B1 (Fm3 ̅m space group) containing amorphous cadmium sulfide were obtained by chemical bath deposition. Upon reaching a critical concentration of the cadmium salt in the reactor, the films consisted of substitutional solid solution and cubic CdS with the B3 structure (F43 ̅m space group). Scanning electron microscopy established the morphological features associated with the secondary nucleation and formation of the cadmium sulfide phase. The structural characteristics of the films have been calculated by a full-profile analysis of X-ray diffraction patterns. We have revealed the correlation between phase and elemental composition of CdxPb1-xS/CdS films with their voltage and current photosensitivity. Based on the received data, we have assumed the role of the individual CdS phase for the photoconductivity mechanism of CdxPb1-xS solid solutions.