Specific Aim 1: Determine whether a behavioral theory-based SMS intervention improves virologic suppression [primary outcome] and retention in care [secondary outcome] for a vulnerable urban HIV-infected population through a randomized trial of this technology compared to SMS appointment reminders alone. Retention in care will also be analyzed as a mediator of virologic suppression. Exploratory outcomes include time to virologic suppression, sustained virologic suppression, emergency department utilization and antiretroviral adherence, as well as levels of depression, positive affect, social support and empowerment.