Three New Jersey-based life sciences firms made the latest Fortune 500, but Pfizer Inc. remains top dog in the industry.

The annual list ranks the world’s largest companies by revenue and provides a good look at how the top Big Pharma firms stack up against each other.

Exxon Mobil leapfrogged Walmart for the top spot on the overall list after raking in $452.9 billion in 2011.

Within pharma, Pfizer remains the biggest firm, coming in at No. 40 after bringing in $67.9 billion in revenue last year. The company is based in New York, but has a large presence in the Garden State.

Meanwhile:

• New Brunswick-based Johnson & Johnson checked in at No. 42 on the strength of $65 billion in profits.
• Whitehouse Station-based Merck & Co. was at No. 57. It brought in $48 billion last year.
• Bristol-Myers Squibb, which had $21.2 billion in profits, came in at No. 134. Like Pfizer, BMS is based in New York but has a heavy New Jersey footprint.
• Finally, Celgene Corp., the Summit-based biotech giant, cracked the Fortune 500 with its No. 492 ranking. The company saw its revenues jump 33.5 percent last year versus 2010, with a total of $4.8 billion.