Cobalt-manganese catalyst is widely studied in Fischer-Tropsch synthesis to obtain light olefins from synthesis gas. However, selectivity and mechanical strength of the catalyst differ depending on its preparation method and type of reactor. The main objective of this paper is to develop a better understanding of manufacturing parameters affecting attrition strength and selectivity of the catalyst. The cobalt-manganese oxide nano-catalysts were prepared using co-precipitation method. The fine powders were then formed using tabletting-crushing (pelletizing) process to obtain the catalyst pellets. The original unformed and formed catalysts were explored for the conversion of synthesis gas to the light olefins in a standard laboratory fixed bed reactor considering selectivity to ethylene and propylene. The processing variables investigated were included of type and concentration of binder and compression pressure in pelletizing process. Furthermore, the attrition assessment of catalyst was carried out using a rotary bottle shake system. The results presented in this work revealed that forming the catalyst under 75 bar compression pressure and 4 wt.% Syton binder led to the maximum selectivity. In the attrition evaluation, it was found that the extent of attrition was the least at the same forming conditions (75 bar, 4 wt.% Syton). (C) 2010 Elsevier B.V. All rights reserved.