The purpose of this study is to conduct a pilot randomized controlled trial (RCT) that provides the feasibility, safety, and preliminary efficacy data required to design a large scale trial evaluating Tai Chi for Chinese Americans with major depressive disorder (MDD) who are not on antidepressant medications.

Aim #1: To evaluate the feasibility and safety of conducting a RCT of Tai Chi for Chinese American adults with MDD who are not on antidepressant medications. The investigators hypothesize that: a) the investigators can develop a Tai Chi intervention and depression-related measurement protocol for Chinese Americans with MDD; b) the investigators will be able to recruit non-pharmacologically treated Chinese Americans with MDD to participate in a randomized controlled Tai Chi study; c) participants will be compliant with the Tai Chi intervention and all testing protocols; d) the Tai Chi intervention will be safe and study staff will be able to effectively monitor participants' depressive symptoms and assure their safety during the study.

Aim #2: To collect preliminary data on the efficacy of a 12-week Tai Chi group intervention for Chinese Americans with MDD who are not on antidepressant medications to determine the effect size needed for a definitive RCT. The investigators hypothesize that at the conclusion of 12-weeks, Tai Chi participants, as compared to control subjects, will demonstrate a) greater improvement in depressive symptoms (Hamilton Depression Severity Index-17, Beck Depression Inventory), b) greater improvement in functional status, general health, and well being (Clinical Global Impressions Scale, The SF-36 Health Survey (SF-36®) for social functioning, Exercise Self-Efficacy, Mindfulness), and c) greater social support (Multidimensional Scale of Perceived Social Support).

Aim #3: To characterize participants' experience in a trial of Tai Chi for Chinese Americans with MDD in order to optimally design a subsequent, more definitive study. Using mixed methods (qualitative and quantitative analyses), the investigators will identify the ethnocultural experience of Tai Chi among Chinese Americans with MDD, assess whether they view Tai Chi a more culturally acceptable alternative to conventional antidepressant therapy, explore the facilitators and barriers to adherence to the Tai Chi training protocol, identify characteristics of responders and non-responders to the Tai Chi intervention, and assess participants' willingness/intention to continue practice of Tai Chi beyond the study period. The investigators hypothesize that a) characteristics such as severity of illness, age, co-morbidities, and education level may distinguish responders from non-responders; b) participants with greater levels of class attendance and home practice will exhibit greater improvements in depressive symptoms; and c) participants who continue to practice Tai Chi after the 12-week training will maintain clinical improvements in depressive symptoms and a lower rate of relapse at the end of 3 additional months of follow-up compared to those who do not continue Tai Chi practice.

Inclusion Criteria:

• Self-identified as being of Chinese ethnicity and fluent in Mandarin and/or Cantonese
• 18-80 years of age
• Satisfy DSM-IV criteria for MDD
• Baseline score of 14-20 on the 17-item Hamilton Rating Scale for Depression (HAM-D-17)
• No regular (≥ 3 times/week for ≥ 2 months) Tai Chi training/practice or other forms of mind-body intervention in the past 6 months

Exclusion Criteria:

• Primary psychiatric diagnosis other than MDD
• History of psychosis, mania, or severe cluster B personality disorder, active ETOH or substance abuse/dependency disorder in the past 6 months
• Unstable medical conditions as judged by investigators
• Use or plan to use confounding treatments, including antidepressants and CAM treatments thought to have beneficial effects on mood, such as St. John's Wort, S-Adenosyl methionine (SAMe), omega-3 fatty acids, light therapy, conventional psychotherapy, mind-body interventions (e.g. Qigong, mindfulness training, muscle relaxation training, etc.)
• Current active suicidal or self-injurious potential necessitating immediate treatment
• Women who are pregnant