Drug addiction is defined as a chronically relapsing disorder that is characterized by compulsive drug taking, inability to limit the intake, and intense drug craving. While the positive reinforcing effects of psychostimulants such as cocaine and amphetamines depend on the mesocorticolimbic dopamine system innervating nucleus accumbens, chronic drug exposure causes stable changes in the structure and function of the brain that may underlie the long-lived behavioral abnormalities in drug addiction. Recent evidence has suggested that various neurotrophic factors and cytokines are involved in the effects of psychomotor stimulants, suggesting that these factors play a role in drug addiction. In this article, a role of neurotrophic factors and cytokines in psychostimulant addiction is discussed.