Titanium dioxide photocatalysis (200mg/L) and photo-Fenton were applied to the treatment of several different pesticides considered priority substances (PS) by the European Commission dissolved in water at 50mg/L or at maximum water solubility (alachlor, atrazine, chlorfenvinphos, diuron, isoproturon and pentachlorophenol) alone (20mg/L of iron) and as a mixture (10mg/L of iron). All tests were performed in new twin 75-L compound parabolic collector (CPC) pilot plants driven by solar energy. Total organic carbon (TOC) mineralisation, disappearance of the parent compound and inorganic ion release are discussed as a function of treatment time. Photo-Fenton treatment was found to be shorter than TiO 2 and more appropriate for these compounds and mixtures of them.