Despite major advances in tobacco control and treatment, tobacco use remains the single largest preventable cause of morbidity and mortality in the US. Smoking prevalence is highest among Texas young adults (ages 18-29) and even higher among those with less than a high-school education and those living in rural areas and at or below the poverty level, such as Latinos. About 19.2% of Latinos ages 18-29 in the study areas are current smokers placing them at higher risk of cancer and other tobacco-related morbidity and mortality. Young adults are heavy users of smartphones, text messaging, social media chats and other mobile social media, providing a remarkable opportunity for innovation in the delivery of health promotion services to reduce health disparities in this large and rapidly growing racial/ethnic population. New social media have an extraordinary theoretical potential for assisting smoking cessation by providing peer modeling and eliciting social reinforcement for behavior change. The goal of this project is to experimentally evaluate Quitxt, a culturally appropriate mobile smoking cessation program. Quitxt - launched by an interdisciplinary research team using proven social cognitive, motivational interviewing, and brief intervention methods for promoting behavior change - blends bilingual text and social media messaging for smoking cessation tailored to the language and culture of young adult smokers in the vulnerable region of South Texas. Quitxt has not been tested in a research study, as its creation as an evidence-based cancer prevention service for young adult smokers was supported by the Cancer Prevention and Research Institute of Texas (CPRIT). To study the effects of Quitxt, the study team will recruit 1,200 young adult (ages 18-29) Latino Spanish- and English-speaking smokers over the 5-year study interval in South Texas. A two-group parallel randomized controlled trial will be conducted to compare rates of smoking cessation: 1) the intervention group will receive the innovative Quitxt text messaging or the chat mobile service; and 2) the usual care group will receive abbreviated text messaging with smoking cessation-related content and referral to the Texas Department of State Health Services (TDSHS) cessation program Yes Quit (www.yesquit.org). The investigators will measure effects online at time of enrollment and again at one, three and six months later. The investigators will validate reports of smoking cessation via biological tests, for those who report smoking cessation at one, three and six-month follow-ups. The investigators hypothesize that the group receiving the Quitxt intervention will achieve significantly higher smoking cessation rates than the group receiving usual care. This study will expand research on the health of young adult Latinos by testing an innovative, mobile, culturally, and linguistically appropriate intervention to reduce smoking among young adult Latino smokers by enhancing their skills development, competence, and self-efficacy to initiate and maintain cessation. Moreover, this study will advance public health by testing the effectiveness of a scalable, evidence-based, easily disseminated, and adaptable intervention with potentially broad national reach to help young adults stop smoking and reduce smoking-related cancer and chronic disease morbidity and mortality and their associated healthcare costs.