BACKGROUND: Length of stay in treatment and coping skills are both predictive of chemical dependence and abuse treatment outcomes. However, little is known about whether coping strategies are related to length of stay in treatment. Because predictors of length of stay in treatment vary by gender, it also may be reasonable to expect gender differences in coping strategies as well as in the relationship between coping and LOS in treatment. METHODS: We examined gender differences in baseline coping strategies, and coping strategies as predictors of length of stay in treatment, among 747 (433 men, 314 women) individuals who entered chemical dependence and abuse treatment in a private, managed care facility. RESULTS: Women reported using more emotional discharge (behavioral attempts to reduce tension by expression of negative feelings), cognitive avoidance (cognitive attempts to avoid thinking realistically about the problem), resigned acceptance (cognitive attempts to react to the problem by accepting it), and seeking support/guidance (behavioral attempts to seek information, guidance, or support). Gender differences for emotional discharge disappeared after we controlled for depressive symptom and drug problem severities. Greater use of seeking alternative rewards (behavioral attempts to get involved in substitute activities and create new sources of satisfaction), less use of emotional discharge, and older age were significant predictors of longer length of stay, with no gender differences found. CONCLUSIONS: This study provides evidence for identifying and decreasing the use of emotional discharge early in treatment, possibly through the use of intervention strategies such as anger management, cognitive restructuring, or motivational interviewing, as well as encouraging an increase in participation in alternative activities.