Last year London welcomed many major congresses, including those for the European League Against Rheumatology and the European Respiratory Society. In 2015, the European Cardiology Society came to the city, bringing over 32,700 delegates.
This year is set to be equally successful, with the European Association of Urology hosting a congress at ExCeL London in March, and the Alzheimer's Association International Conference taking place in July.
Next year, London will be welcoming a number of international congresses, such as the American Association of Petroleum Geologists in October and the International Association for Dental Research.
Commenting on the news, Suzanne Singleton, head of associations at London & Partners said: "The ICCA rankings are a key indicator of a city's success in the meetings and events sector and we are very proud that London has maintained its position in the top 5. This result highlights the important collaboration with our partners across the city."
• For more breaking news and in-depth features, sign up to C&IT Magazine's daily Newstracker here