Manufacturers
- M & M Electronics
- M.C. Jones Electronics
- M2 Antenna Systems Inc.
- Mackie Designs Inc.
- Madell Technology
- Magnavox
- Magnum Dynalab
- Mallinckrodt
- Maquet
- Marantz
- Marconi
- Marconi Adret Instruments
- Mark Levinson
- Märklin
- Marquette Hellige GmbH
- Marshall
- Maximillian Associates
- Maytag
- Mazda
- McCarthy
- MCData Corporation
- McIntosh
- McMichael
- McMurdo Silver Company
- Medical Research Laboratories Inc.
- Medtronic Physio-Control
- Megger
- Meissner
- MELAG Medical Technology
- Melco
- Mennen Medical Ltd.
- Mercury Electronics Corp.
- Metermann
- Metex
- Metrix
- Metron
- Metz
- Micro Medical Limited
- Micro Seiki
- Micronta
- Midea
- Midland International Corporation
- Miele
- Mimaki
- Mindray
- Mini-Products Inc.
- Minolta
- Minolta-QMS
- Mipro
- Mirage Communication Equipment
- Misaki Inc.
- Mitaka Kohki
- Mitsubishi
- Moog Music
- Morrow Radio Manufacturing Co.
- Mosley Electronics Inc.
- Motorola
- MSI Micro-Star International
- Mullard
- Multi-Elmac
- Murphy
