This proposal describes a combined laboratory and clinical trial preliminary investigation to advance medication development for cocaine dependence. The main objective is to test whether intranasal Oxytocin could reduce relapse risk by reducing stress sensitivity. To measure the stress sensitivity, this study will evaluate a new stress challenge: a) Intranasal desmopressin, a vasopressin analog, will be used an endocrine stressor; its effects will be evaluated by serial measurements of serum Adrenocorticotropin hormone (ACTH), and self reports; b) if pretreatment with intranasal oxytocin dampens the ACTH and subjective response to intranasal desmopressin. These measures will be tested during a 7-day inpatient abstinence induction hospitalization. For those patients with family and work obligations, an outpatient abstinence induction procedure is available. The response to the desmopressin challenge will be compared to a cohort of matched control subjects. After abstinence induction, cocaine dependent patients enter a 6-week, double blind, randomized, placebo-controlled trial of 24 IU of intranasal oxytocin vs. placebo, to monitor if this reduces the relapse risk.