An RC-IED is a bomb, prepared in an improvised manner containing destructive, lethal, noxious, pyrotechnic, or incendiary chemicals and designed to destroy or incapacitate personnel or vehicles. In some cases, RC-IEDs are used to distract, disrupt, or delay an opposing force, facilitating another type of attack. RC-IEDs may incorporate military or commercially sourced explosives, and often combine both types, or they may otherwise be made with homemade explosives.

RC-IEDs are used in terrorist actions or in unconventional warfare by guerrillas or commando forces. In the second Iraq War, they were used extensively against US-led Coalition forces and by the end of 2007 they had become responsible for approximately 63% of Coalition deaths in Iraq. They are also used in Afghanistan by insurgent groups, and have caused over 66% of the Coalition casualties in the 2001–present Afghanistan War.