In the present study an oily wastewater from the lubricant unit of a petroleum company was evaluated by combining the sequence photo-assisted oxidation-Pseudomonas putida DSM 437. The wastewater contained various alcohols, acids and phenolic compounds. From the above mentioned compounds the biodegradation of ethylene glycol, phenol, o-cresol and p-cresol was examined. The direct biodegradation of the wastewater using P. putida DSM 437 resulted in 85% ethylene glycol assimilation while phenol, o-cresol and p-cresol assimilation was in the range of 27% to 40%. In order to increase the degradation of the phenolic compounds photo-assisted oxidation was applied to the wastewater using UV/ H2O2 its a pretreatment step to biological degradation. Fc(III) were used in order to accelerate the formation of the hydroxyl radicals and consequently the overall photo-oxidation process. The addition of Fe(III) ions resulted in 30% decrease of COD within the first 10 min while the respected value without iron ions was 5%. The combined photo-assisted oxidation and biodegradation of the wastewater resulted in 100% removal of ethylene glycol. The overall degradation of phenol was 78% while the 59% and 84% of the initial o-cresol and p-cresol respectively, were removed from the wastewater. The combined process resulted in 72% of COD removal.