Chelsio Communications is a privately held technology company headquartered in Sunnyvale, California with a design center in Bangalore, India.

Chelsio was an early vendor of 10 Gigabit Ethernet technology, announcing a product in 2004,[7] an alliance with Foundry Networks,[8] and measurements in 2005.

[11] The company holds several patents, dating from one for reduced overhead direct memory access (DMA) initially filed in 2002.

[13] In January 2013 Chelsio announced the Terminator 5 application specific integrated circuit, which brings all of the company's protocol acceleration technology to 40 Gbit/s speeds, with the roadmap to 100 Gbit/s scheduled for 2015.

[15] The Chelsio Unified Storage Router product is also marketed by Dell,[16] and was certified to work with tape drives from Quantum Corporation in 2011.