There are a growing number of adolescents with chronic medical conditions in the United States. The Advisory Committee on Immunization Practices (ACIP) recommends HPV vaccination and annual influenza vaccination of all adolescents. Pneumococcal polysaccharide vaccination is also recommended for certain high-risk patients. Limited studies suggest that vaccination coverage of this population remains sub-optimal. Text message vaccine reminder/recall has been shown to be effective in increasing uptake of select pediatric and adolescents vaccines, but has yet to be examined among patients with chronic medical conditions who may also face unique barriers to vaccination. This intervention aims to implement and evaluate the use of text message vaccine reminders among urban low-income minority adolescents with chronic medical conditions. This investigator-initiated study is supported in part by a grant from the Pfizer Medical Education Group.