The multi-walled nanotubes (MWNTs) have been synthesized in large scale by using metal formate as catalyst precursors. The calcium carbonate is used as catalyst support, it is chosen because of its non toxic and easily soluble nature. The synthesis was carried out by chemical vapor deposition method for 15 min under optimized conditions. The products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and X-ray diffraction (XRD) method. The purity of the as grown products and purified products were determined by thermal analysis. The obtained yield of MWNTs was about 8300 wt% relative to the nickel catalyst. This synthesis route avoids the lengthy process of calcination and reduction for the preparation of catalysts hence this method is more economical. This economical and environmental friendly synthesis route can be used for synthesizing MWNTs in large scale.