The company said last month when it released its quarterly earnings that it would cut about 11% of its 39,000-strong workforce.
Sun began notifying US employees affected by the job cuts on Monday. Local rules will govern the layoff process in other parts of the world, according to Sun spokeswoman Diane Carlini.
The reductions are based on a "needs analysis" completed by each of Sun's business units. Carlini declined to say which business units or regions of the world would bear the brunt of the cuts.
"We announced these cuts during our earnings call in October," Carlini said. "It's part of our continuing efforts to return Sun to profitability."
This is the second time in 18 months that Sun has laid off staff. Last year, the company reduced its workforce by about 3,900 employees. The latest round of cuts will reduce Sun's worldwide workforce to about 35,000 employees - about 20% fewer than it employed 18 months ago.
Sun will take a charge of approximately $300m ($189m) in the second quarter of 2003 as a result of the workforce reductions.