Pyromania refers to an Impulse-Control Disorder involving the persistent, compelling and irresistible urge to start or to set fires. It is also defined as a pattern of deliberate setting of fires for pleasure or satisfaction derived from the relief of tension experienced before the fire-setting.

The name of the disorder comes from two (2) Greek words that mean "fire" and "loss of reason" or "madness." The clinician's handbook, the Diagnostic and Statistical Manual of Mental Disorders (DSM) classifies Pyromania as a disorder of impulse control, meaning that a person diagnosed with Pyromania fails to resist the impulsive desire to set fires as opposed to the organized planning of an arsonist or terrorist.
DSM-IV-TR specifies six (6) criteria that must be met for a patient to be diagnosed with pyromania:
(1) The patient must have set fires deliberately and purposefully on more than one occasion;
(2) The patient must have experienced feelings of tension or emotional arousal before setting the fires;
(3) The patient must indicate that he/she is fascinated with, attracted to, or curious about fire and situations surrounding fire (for example, the equipment associated with fire, the uses of fire, or the aftermath of firesetting);
(4) The patient must experience relief, pleasure, or satisfaction from setting the fire or from witnessing or participating in the aftermath.
(5) The patient does not have other motives for setting fires, such as financial motives; ideological convictions (such as terrorist or anarchist political beliefs); anger or revenge; a desire to cover up another crime; delusions or hallucinations; or impaired judgment resulting from substance abuse, dementia, mental retardation, or traumatic brain damage; and
(6) The fire setting cannot be better accounted for by anti-social personality disorder, a conduct disorder, or a manic episode.

Other definition:

Pyromania refers to the pathological compulsion to set fires.