This paper presents the results of an experimental investigation into the influence of a ferrous picrate based homogeneous combustion catalyst on fuel consumption and smoke emission of a laboratory diesel engine. The catalyst used in this study was supplied by Fuel Technology Pty. Ltd. The fuel consumption and smoke emission were measured as a function of engine load, speed and catalyst dosing ratio. The brake specific fuel consumption and smoke emission decreased as the dosing ratio of the catalyst doped in the diesel fuel increased. At the catalyst dosing ratio of 1:3200, the brake specific fuel consumption was reduced by from 2.1% to 2.7% and the smoke emission was reduced by from 6.7% to 26.2% at the full engine load at speeds from 2600 rpm to 3400 rpm. The results also indicated that the potential of the fuel saving seems to be greater when the engine was run under light load. (C) 2011 Elsevier Ltd. All rights reserved.