Background & Aims: Methadone maintenance therapy is one of the treatment choices for opiate users. Understanding opiate dependants’ experiences of their treatment period is important for continuing the treatment with methadone and assessing their experiences may help to revise the standards of methadone centers and thus to improve the quality of treatment. This study aims to describe the structure and essence of opiate dependants’ experiences with methadone centers during treatment. Method: It was a qualitative phenomenological approach in which participants were selected from opiate dependants referred to methadone centers in Kerman city in 2007 by applying purposive sampling continued until data saturation and obtaining a sample size of 32 participants. Data were collected by in-depth interviews. Colaize s Method was applied for data analysis. The rigor of the present study was based on transferability and credibility. Results: In whole, 26 themes were extracted and put into structural components. The structural components were put into topical components including: 1- positive therapeutic alliance 2- negative therapeutic alliance and 3- therapeutic alliance requests. These components show the basic structure of participants’ experiences of therapeutic relationship in methadone centers. Conclusion: Client – based strategy in methadone clinics, not only leads to a positive therapeutic alliance, but can persuade patients to continue their treatment programs for long time period. Establishing a good relationship with patients in methadone centers during treatment procedure is an effective way to meet the goals of methadone maintenance treatment.