Experiments were conducted on the Fe3O4/FeO metal oxide system under pure methane and pure steam environments in a thermogravimetric analyser (TGA) and a prototype-miniaturised micro-reactor. Experimental results show that during a typical fuel oxidation step the concentration of methane in the product gas stream gradually decreases while Fe3O4 is being reduced to FeO. However, on or about a fractional conversion of 60% the slope of the CH4 plot sharply increases due to catalytic effects of FeO on methane decomposition. Similarly, the H-2 plot associated with steam reforming step picks up rapidly and reaches a maximum of 98% at a fractional conversion of 30%. The conversion times of steam and fuel in the micro-reactor were generally shorter than conversion times obtained in the TGA system. The experimental results provided two vital pieces of information: (i) the chemical looping steam reforming cycle is technically viable, and (ii) the performance of the process at micro-scales needs to be further understood before high throughput miniaturised reformers could be designed and built. (C) 2011 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.