Kerala Tourism Secretary Suman Billa received the award at a ceremony held on Thursday.
In a first, Kerala Tourism won the gold prize for its print campaign titled "The Great Backwaters" launched last year, beating tough competition from major tourism boards of the world.
The print campaign presents the state's famous water bodies as a single destination and once-in-a-lifetime experience for the traveller, in the big league of the Great Wall of China and the Great Barrier Reef of Australia.
This is the third honour in as many months for Kerala Tourism at the international and national level.
In January, it won the United Nations World Trade Organisation Ulysses Prize, a first for India, for excellence and innovation in tourism. Last month, it took home four prizes at the National Tourism Awards for 2012-13.
"We are truly honoured by this remarkable recognition from the world's biggest travel trade show," said Kerala Tourism Minister A.P. Anil Kumar.
"It is a huge achievement for Kerala and a major boost to the state's reputation as one of the top tourism destinations in the world," said Billa.
The Das Goldene Stadttor or the Golden City Gate awards, held under the patronage of the German Federal Association of Film and Audio-Visual Producers, are considered the ultimate recognition in global tourism communication.
Started in 1966, ITB-Berlin is the world's leading travel trade show, with the Who's Who of the tourism and travel industry present at the event, where 180 countries participate.