Wastewater generated during coke-oven gas cleaning operations in the integrated steel plant contains phenol, cyanide, thiocyanate, and also oil and grease. Although the activated sludge process is widely practiced for biological treatment of coke-oven wastewater, it was observed during the evaluation of performance of full scale coke-oven wastewater treatment plant that oil contamination and poor sludge settleability had resulted in poor maintenance of the activated sludge process. Keeping these aspects in view, treatability studies were conducted and an alternative treatment process is proposed. With these corrective measures the coke-oven wastewater treatment plant will give desired performance. In this paper we present results of the performance evaluation, data on treatability studies and alternative treatment process scheme.