The degradation processes of dibutyl phthalate (DBP), an important pollutant, are rather slow and do not lead to the complete decomposition. In the present work the photocatalytic degradation of dibutyl phthalate in the presence of was studied. Experiments were carried out in suspensions and with immobilized layers, prepared from powder suspensions and by sol-gel technique. Two different polychromatic light sources (band maxima at and ) were used for irradiation. The results confirmed that the photocatalytic degradation of DBP using is an efficient degradation process and proceeds even at very low concentration of photocatalyst . Reaction rates were significantly higher in the case of the lamp with the maximum at , which is due to the higher light intensity of this lamp. At comparable amount P25 layers exhibit about 50% of photoactivity using suspension.