MCI

MCI may refer to the following:
* MCI WorldCom, Inc., a former American telecommunications company acquired by Verizon Communications
* Microwave Communications Inc., later MCI Communications, the corporation that operated as MCI from 1963â€"1998
* The airport code for the Kansas City International Airport in Kansas City, Missouri, USA
* Maine Central Institute, a boarding school in Maine, founded in 1866
* Martingrove Collegiate Institute, a high school located in Etobicoke, Toronto, Canada
* Media Control Interface/Multimedia Control Interface.
* Mild cognitive impairment, a neurological affliction often associated with Alzheimer's disease
* Motor Coach Industries, a company that builds buses
* MCI (audio), a company that manufactured multi-track audiotape recorders for professional studio recording
* Massachusetts Correctional Institution, a list of which can be found at List of Massachusetts state prisons
* Malicious Caller Identification, a type of enhanced telephone service
* Macroinvertebrate Community Index, a measure used in New Zealand for the environmental status of streams.
* Myocardial infarction, a heart attack.
* Master Command Interface, The main terminal for a computer