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The General Mobile Radio Service (GMRS) is a land-mobile FM UHF radio service designed for short-distance two-way communication. It requires a license in United States but some GMRS compatible equipment can be used license-free in Canada. The United States permits use by adult individuals who possesses a valid GMRS license, as well as their immediate family members.[a] Immediate relatives of the GMRS system licensee are entitled to communicate among themselves for personal or business purposes, but employees of the licensee who are not family members are not covered by the license non-family members must be licensed separately.

GMRS radios are typically handheld portable devices much like Family Radio Service (FRS) radios, and share the FRS frequency band near 462 and 467 MHz. Mobile and base station-style radios are available as well, but these are normally commercial UHF radios as often used in the public service and commercial land mobile bands. These are legal for use in this service as long as they are GMRS type-approved.

Any individual in the United States who is at least 18 years of age and not a representative of a foreign government may apply for a GMRS license by completing the application form, either on paper or online through the FCC's Universal Licensing System. No exam is required. A GMRS license is issued for a 10 year term. The fee is $70 for most applicants.

A GMRS individual license extends to immediate family members and authorizes them to use the licensed system. GMRS license holders are allowed to communicate with FRS users on those frequencies that are shared between the two services. GMRS individual licenses do not extend to employees.

New GMRS licenses are being issued only to individuals. Prior to 31 July 1987, the FCC issued GMRS licenses to non-individuals (corporations, partnerships, government entities, etc.). These licensees are grandfathered and may renew but not make major modifications to their existing licenses.

In any case, each GMRS station must be identified by transmission of its FCC-assigned call sign at the end of a transmission or a series of transmissions, and at least once every 15 minutes for a series lasting more than 15 minutes. The call sign may be spoken or sent with audible tones using Morse code. A repeater station handling properly identified transmissions of others is not required to send its own station identification (47 CFR §95.1751).

The GMRS-only channels are defined in pairs, with one frequency in the 462 MHz range for simplex and repeater outputs, and another in the 467 MHz frequency range for repeater inputs. There are eight channels exclusively for GMRS and seven “interstitial” channels shared with Family Radio Service. GMRS use requires an FCC license, and licensees are permitted to transmit at up to 50 watts on GMRS frequencies, depending on the type of station, but 1 to 5 Watts is more common. Units are allowed to have detachable or external antennas.

GMRS licensees are also able to use the first seven of the FRS frequencies (the “interstitial” GMRS frequencies) with a few limitations. Specifically, they may be used as long as one-way pages are not transmitted, communications are limited to voice, and transmission power (ERP) does not exceed 5 Watts (FCC Code §95.29, section f). This allows GMRS users to transmit on a total of 15 channels. FRS channels 8 through 14 are not available for GMRS use; use of these frequencies requires an FRS transceiver, or a hybrid transceiver operating under FRS rules.

Hybrid FRS/GMRS consumer radios have been introduced with 22 channels, instead of the 14 channels associated with FRS. On this type of radio, transmitting on shared FRS/GMRS channels 1–7 requires a license if using more than 0.5 Watt. Channels 8–14 are strictly license-free FRS channels. Transmitting on GMRS-only channels 15–22 requires a license. It is the responsibility of the radio user to read and understand all applicable rules and regulations regarding GMRS. These hybrid radios are often referred to as “bubble pack” radios, since they are often packed in a plastic shell, for hanging on a display shelf. The massive sales of these radios have led to the term “bubble-pack pirates”, persons who use GMRS without a license.

Effective 28 September 2017, FCC revised the definition of the FRS service. FRS operation is now permitted with up to 2 Watts on the shared FRS / GMRS channels. The FCC will not grant type acceptance for hybrid radios that would exceed the limits for the FRS service on the FRS channels. Current “hybrid” FRS/GMRS radios will not require a GMRS license for power up to 2 Watts, but FRS radios will still not be permitted to use the input frequencies of GMRS repeaters. Any radio exceeding the limits of the new FRS service will be classified as a GMRS radio.

The FCC rules for use of hybrid radios on channels 1–7 require licensing only when operating under the rules that apply to the GMRS.[11] Many hybrid radios have an ERP that is lower than a half-watt on channels 1–7, or can be set by the user to operate at low power on these channels. This allows hybrid radios to be used under the license-free FRS rules if the ERP is less than one half watt and the unit is certified for FRS operation. Only two makers of hybrid FRS / GMRS radios (Garmin and Motorola) presently sell radios that will operate on the GMRS repeater channels; the common “22 channel” radios cannot be used with GMRS repeaters. The Icom IC-F21GM is a solely-GMRS radio that will also work with repeaters. FRS rules permit only 2.5 kHz (Narrowband FM) frequency deviation on the FRS shared channels. GMRS uses ±5 kHz deviation on the GMRS channels.

Effective 30 September 2019, it becomes unlawful in the USA to import, manufacture, sell, or offer to sell radio equipment capable of operating under both GMRS and FRS.

New GMRS/FRS Frequency chart effective 28 September 2017.

In the table below, the so-called “Friendly Name” of a frequency is the portion of the frequency to the right of the decimal (the kHz portion). For example: the “friendly name” for 462.550 MHz is “550”.

This first set of frequencies shows the split frequency pairs used in duplex operational mode, often used with repeaters. Simplex (same frequency for receiving and transmitting) mode only utilizes the lower set of frequencies.

GMRS radio channels in the table below use 5 kHz deviation and 25 kHz channel bandwidth although some “bubble pack” combo FRS/GMRS radios utilize 2.5 kHz deviation. For best compatibility of audio level, 5 kHz deviation should be used when communicating with GMRS equipment. The 4-digit decimal GMRS frequencies (shared FRS 1-7 / ICOM 9-15) are spaced 12.5 kHz from the (ICOM 1-8) GMRS frequencies, and may receive interference from other nearby stations. It may be advisable to use 12.5 kHz narrow-band (NFM) in congested areas, or avoid their use as a last resort.

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