Addiction is a chronic and progressive disease which leads to biological, psychological, and social manifestations and is characterized by inability to consistently abstain, impairment in behavioral control, and craving, and a dysfunctional emotional response. Drug addiction is one of the most important problems in our country. Methamphetamine is an extremely potent psycho-stimulant and highly addictive drug, accompanied by cheap price, ease of synthesis and long lasting effects (Henry, Minassian, & Perry, 2005; Shoptaw et al., 2008; Weber et al., 2012). In the current decade, methamphetamine use is becoming one of the most serious social concerns in Iran. There are currently no drugs approved to treat meth addiction. The main challenge in treating drug addiction is relapse phenomena. It has been estimated that 80 percent of addicts who get off drugs in detoxification phase, go back to drugs within a year. The key component of the relapse is the phenomenon of craving, or the powerful "hunger" for drugs that can linger months or years after abstinence. Thus reducing drug craving can be a major breakthrough in the field of addiction treatment. On the one hand there are currently no effective drugs approved to control meth craving. On the other hand, the recent studies indicate that the new advances in non-invasive brain stimulation techniques, can open new horizons in the addiction treatment. Transcranial direct current stimulation (tDCS) might be considered a neuromodulatory intervention. TDCS polarizes the exposed tissue and modifies spontaneous neuronal excitability and activity by a tonic de- or hyperpolarization of resting membrane potential. The efficacy of tDCS to induce acute modifications of membrane polarity depends on current density. In addition, there are several promising studies that support from effect of this type of stimulation over the dorsolateral prefrontal cortex (DLPFC) in reducing craving of methamphetamine (Shahbabaie et al 2001), cigarette (P. Boggio, Liguori, & Sultani, 2009; Fregni, Liguori, et al., 2008), alcohol (Boggio et al., 2008), marijuana (Boggio et al., 2010) and food (Fregni, Orsati, et al., 2008; Goldman et al., 2011). However, there are two main problems in published studies on tDCS. For one, there is still no consensus on the choice of the electrodes’ montage (position of anode and cathode electrodes). To our knowledge (March 2014), There are no studies comparing the effectiveness of various montages on craving. The other problem is that most published studies in this regard are single-session. Although valuable in research phase, these studies come short in clinical application. There is a need to design various multiple session clinical trials, in order to achieve clinically applicable results of this new technology. In the current study, we plan to cover these two pitfalls. This study can be a trigger to move tDCS technology towards clinical application in addiction medicine All that been said, our study will have two phases: In the first phase, 120 methamphetamine dependents will be randomly assigned to six groups with different montages in order to find the most effective electrode montage (with relevant theoretical and/or empirical literature for each). The different montages are as follows: 1) Anode on the right DLPFC, cathode on the left arm 2) Anode on the left DLPFC, cathode on the right arm 3) Anode on the left DLPFC, cathode on the right DLPFC 4) Anode on the right DLPFC, cathode on the left DLPFC 5) The first Anode electrode on the right DLPFC and the second one on the left DLPFC, cathode on the arm 6) Sham stimulation The second phase of the study will start after finding the most efficient montage. At this point, in order to evaluate cumulative effect of tDCS on craving, we will apply the chosen montage in a randomized double blinded clinical trial for 10 sessions (2 weeks). The study will include two groups (experiment and control) of 30 methamphetamine dependents.