This follows the departure of Malcolm Wall Morris, who has resigned to follow a new career path.
Sashittal, who has been DMCC's chief operating officer since December 2009, has had more than 25 years of experience in the energy, resources and financial markets.
"Gautam is the best choice to take over as DMCC CEO," Ahmed Bin Sulayem, executive chairman of DMCC said in a statement.
"We have worked together for many years and I have the utmost respect for his deep knowledge of the commodity and financial markets. Gautam will continue to lead DMCC's contribution to Dubai's economic success by driving business growth and expansion, positioning Dubai as the world's leading commodities eco-system," he added.