Display omitted •Cytarabine degradation by TiO2/SSL, TiO2/S2O82−/SSL and TiO2/H2O2/SSL processes.•The effect of operational parameters and addition of oxidants was studied.•Hydroxylation and oxidation were found as the main transformation routes before ring cleavage.•OH radicals were the major oxidant species based on scavenging experiments.•Microtox bioassay toxicity increased at the first stages but nearly eliminated at the end-stages. The photochemical degradation of antineoplastic drug cytarabine (CY) by TiO2 photocatalysis under simulated solar light (SSL) radiation, TiO2/S2O82−/SSL and TiO2/H2O2/SSL processes was investigated in the present study. Experimental results indicated that CY was quickly degraded in all the studied treatments and degradation kinetics were dependent by all studied variables (i.e. catalyst dose, initial CY concentration, pH, oxidant concentration). In addition to kinetic studies, the transformation products (TPs) generated during the treatments were investigated using liquid chromatography coupled to high resolution mass spectrometry while mineralization was also followed by ion chromatography and total organic carbon measurements. Based on the identification of TPs and scavenging experiments, the major transformation routes followed were hydroxylation and subsequent oxidation, in all studied treatments. Microtox bioassay was applied before and during the TiO2 photocatalytic process, in order to investigate the potential risk of CY and its TPs to aqueous organisms. The obtained results showed an increase in the acute toxicity in the first stages and a continuously decrease afterwards, leading to very low toxicity levels within 360min of TiO2/SSL treatment. Overall results indicated that photocatalytic degradation of CY can lead to its complete elimination and detoxification of the solution.