The new facility, located in Tema, will produce cocoa liquor, butter and powder.
Capacity will start off at 65,000 metric tones, with the potential to almost double, said the firm.
West Africa currently produces nearly three-quarters of the world's cocoa, and Cargill said its investment in Ghana will complement its other cocoa producing facilities to help meet increasing demand from customers around the globe.
"This plant will incorporate some of the latest technology to ensure Ghanaian cocoa is processed to the highest standards," said Paul Naar, head of Cargill's Food Ingredients businesses in Europe, Middle East and Africa.
" Ghana is one of the most important cocoa supplying countries in the world and creating value-added products in Ghana will not only be good for the people of Ghana, but will also allow us to provide a greater range of cocoa products to meet the growing needs of our cocoa customers around the world.
We realize how fortunate we are to have access to such high quality cocoa and are grateful for the continued support and leadership of the Ghanaian Government."
A long-term supply agreement was signed between Cargill and the Ghana Cocoa Board in June 2006, paving the way for the construction of the new facility.
Attendees at last week's ceremony for the ground-breaking at the new site included Ghana's president John Kufuor, US Under Secretary of Agriculture Mark Keenum and chief executive of the Ghana cocoa board Isaac Osei.
"We are delighted that Cargill has chosen Ghana to build a world-class cocoa processing facility," said President Kufuor.
"Cargill is a well-respected private company whose involvement in our country will create jobs, benefit farmers, and contribute to the local community."
Ghana has also been the subject of expansion for the cocoa business of other ingredients firms.
Earlier this year, major Swiss cocoa processor Barry Callebaut expanded operations at a factory in Tema - doubling the facility's bean processing capacity from 30,000 tonnes to 60,000 tonnes.
Ghana is the world's second largest cocoa producing region and the country's government has pledged to increasing bean production to over 1 million tonnes.
According to the International Cocoa Organisation (ICCO) the country's commercial crop in 2005/2006 reached a record high of 646,000 tonnes.