In this paper, we studied Fenton and photo-Fenton-advanced oxidation processes for degradation of alkylphenolic compounds under various experimental conditions. Bisphenol A (BPA) has been degraded more slowly than 3,5-dimethylphenol (3,5-DMP) and 2,5-dimethylphenol (2,5-DMP), but faster than 2,4,6-trimethylphenol (2,4,6-TMP) under the same experimental conditions (ratios of Fe2+/Organic Substrate=2, H2O2/Organic Substrate=14). Mineralization rate of BPA was increased by irradiation of Fenton reagent with UV light (photo-Fenton, 40 W UV lamp), and 89% of mineralization was achieved for 700 ml solutions, while only 63% mineralization was observed in absence of UV-light (Fenton) at 250 min reaction times. Considerable excess of H2O2 in reaction medium caused decreases in mineralization efficiency, due to scavenging the hydroxyl radicals generated in Fenton and photo-Fenton reactions. The efficiency of the degradation was improved by loading H2O2 into reaction medium in small amounts at various time intervals.