Catalytic chemical vapour deposition (CCVD) is one of the methods used for large scale production of carbon nanotubes (CNT). In this paper the results of the experiments conducted to study the role of Ca and Mg oxides, hydroxides and carbonates as supports for iron, cobalt and a mixture of iron-cobalt catalysts, in the production of CNT by CCVD method are reported. Acetylene and ethylene were used as the two different sources of carbon and N-2 as the carrier gas. The syntheses reactions were conducted at 700degreesC under ambient pressure in a horizantal tubular furnace. Almost all the support-catalyst mixtures were found to be active in the formation of CNT. The quantity and quality of the tubes produced in different synthesis reactions were however, significantly different. Out of the several supported catalysts used calcium carbonate and magnesium oxide were found to give the best yield of carbon deposit when they were used as supports for a mixture of cobalt and iron. The yield of carbon deposit was found to be very poor when these supports had only Fe. Cobalt on the otherhand showed better activity than iron. A simple method of purification of crude carbon deposit is also described. The density and the quality of nanotubes were analysed by TEM. The CNT produced were found to be multiwall in nature. (C) 2004 Elsevier B.V. All rights reserved.