Metal oxide semiconductors are of great technological importance in environmental remediation because they can generate charge carriers when stimulated with the required energy. ZnO and TiO2, both well-known photocatalysts, were taken into account for our study because of their practical, inexpensive, non-toxic behavior, high photosensitivity, stability, and increased activity towards photocatalytic degradation of organic pollutants. The study examined the photodegradative efficiency of ZnO and TiO2 in the degradation of a model drug (amoxicillin) and a model dye (methylene blue) in aqueous solutions. The degradation of the amoxicillin was carried out mainly under UV radiation in the presence of zinc oxide or titanium dioxide while methylene blue under visible light. Solutions were then analyzed by UV-Vis spectroscopy in order to assess the photocatalytic efficiency.