C&IT readers voted the hotel, which offers a Six Sense spa, seven bars and restaurants, as top performer in both categories.
Hotel Arts Barcelona general manager and regional vice president Victor Clavell said: "It is a great honour to receive both of these distinctions in an increasingly competitive market."
Mauritius' Le Touessrok picked up silver in the Best Overseas Incentive Hotel category, while Dubai's Atlantis property won bronze.
The Fairmont Monte Carlo won silver in the Best Overseas Conference Hotel section, with Paris George V taking bronze.
The C&IT Hot List 2009 is designed to celebrate the best destinations, venues and suppliers for events across 12 categories, as voted for by C&IT readers, with gold, silver and bronze place awarded in each.
More than 400 event planners representing some of the biggest brands and their corporate travel budgets voted across an eight-week period.
The winners received recognition at a gala event held at Axis at One Aldwych in London on 30 September.
The full list of Gold winners are as follows:
Best Conference Destination: London
Best Incentive Destination: Cape Town
Best UK Conference Hotel: Celtic Manor
Best Overseas Conference hotel: Hotel Arts Barcelona
Best UK Incentive Hotel: Chewton Glen
Best Overseas Incentive Hotel: Hotel Arts Barcelona
Best Conference Centre: Excel London
Best Unusual Events Venue: Sealife London Aquarium
Best DMC: Vista Events (Greece)
Best Venue for Sustainability: ACC Liverpool
Best Transport Provider: British Airways
Best Hotel Chain: Four Seasons