The frequent co-occurrence of mental and substance use disorders (“dual diagnosis”) has created a role for addiction-trained psychiatric consultants in drug and alcohol treatment programs. The complex treatment needs of the dually diagnosed require that the consultant psychiatrist have knowledge about the existing treatment models of chemical dependency, the recovery process, and the complex relationship between substance abuse and psychopathology. This paper reviews the existing clinical models for understanding and treating chemical dependency and then proposes an approach to consultation practice that employs a developmentally-based clinical model. The consultation work of three academic addiction psychiatrists who utilize a developmental approach is described. The demographic and diagnostic characteristics of their consultation cases from three substance abuse inpatient rehabilitation programs for a 1-year period are summarized. Five major tasks for addiction psychiatry consultants are identified and discussed: diagnostic evaluation, identification of recovery barriers, identification of relapse triggers, recovery-oriented brief psychotherapy, and pharmacotherapy.