© 2015 Copyright © Taylor & Francis Group, LLC. Outpatient treatment practices for adolescent substance users utilize retrospective self-report to monitor drug use. Cell phone-based ecological momentary assessment (CEMA) overcomes retrospective self-report biases and can enhance outpatient treatment, particularly among Latino adolescents, who have been understudied with regard to CEMA. This study explores compliance to text message-based CEMA with youth (n = 28; 93% Latino) in outpatient treatment. Participants were rotated through daily, random, and event-based CEMA strategies for 1-month periods. Overall compliance was high (>80%). Compliance decreased slightly over the study period and was less during random versus daily strategies and on days when alcohol use was retrospectively reported. Findings suggest that CEMA is a viable monitoring tool for Latino youth in outpatient treatment, but further study is needed to determine optimal CEMA strategies, monitoring time periods, and the appropriateness of CEMA for differing levels of substance use.