(Fortune) -- Halliburton (Charts) ranks no. 306 on FORTUNE's Global 500 this year, with $21.0 billion in revenues, up 2.6% from the previous year. The Houston, Texas-based company was ranked no. 286 on the 2005 list. Its 2005 profits were $2.4 billion.

2005 was a banner year for most Global 500 companies. It took $13.7 billion in revenue just to make this year's list - up from $12.4 billion last year. And profits for the 500 companies jumped 30%. Total revenues for the Global 500 in 2006 add up to $18.9 trillion, a third of the world's GDP.

In the Oil and Gas Services industry, the world's biggest companies are: Schlumberger Limited (Charts), ranked no. 477 on the Global 500 with $14.3 billion in revenues.

The Global 500 list is an annual ranking of the world's largest corporations by revenues.

Next: Full list: 2006 Global 500 at http://money.cnn.com/global500

Plus: See Halliburton's Global 500 details, including financial stats and contact information.