In this paper, the multi-response optimization of grade and recovery simultaneously using Taguchi quality loss function has been done for Zonguldak/Turkey bituminous coal by oil agglomeration. The controllable factors selected in this investigation are solid content, amount of oil, agitation time and agitation rate. The percentage contribution of each controllable factor has been determined on the performance of oil agglomeration. The amount of oil has been found as the most effective factor and its contribution is 65.42% on multiple quality characteristics. The confirmation experiment has also been carried out according to the optimum conditions predicted. The grade and recovery have been increased up to 0.565% and 93.04%, respectively against the initial value of grade and recovery as 0.436% and 75.08%, respectively. The results show considerable improvement in both the quality characteristics such as grade and recovery with the multi-response optimization used, as compared the initial value of grade and recovery. (C) 2010 Elsevier B.V. All rights reserved.