Background: In the U.S., Latinos report particularly high levels of inactivity and related chronic illnesses and are in need of intervention. Thus, the purpose of the current study was to culturally and linguistically adapt an empirically supported, individually tailored physical activity print intervention for Latinos and then conduct an RCT of the modified program. Design: An RCT was conducted. Setting/participants: The sample included 93 overweight/obese (80%) Latinas with low income and acculturation. Intervention: Data were collected in 2007-2008 and analyzed by intent-to-treat in 2009. Participants were randomly assigned to either (1) a culturally and linguistically adapted physical activity intervention (Seamos Activas) or (2) a wellness contact control condition. Main outcome measures: Self-report physical activity, as measured pre- and post-intervention (6 months, 87% retention) by the 7-Day Physical Activity Recall. Results: Moderate-intensity (or greater) physical activity increased from an average of 16.56 minutes/week (SD=25.76) at baseline to 147.27 (SD=241.55) at 6 months in the intervention arm (n=45), and from 11.88 minutes/week (SD=21.99) to 96.79 (SD=118.49) in the wellness contact control arm (n=48). No between-group differences were seen in overall physical activity. Intervention participants reported significantly greater increases in cognitive (F[1, 91]=9.53, p=0.003) and behavioral processes of change (F[1, 91]=8.37, p=0.005) and available physical activity supplies and equipment at home (F[1, 91]=4.17, p=0.04) than control participants. Conclusions: Results supported the hypothesized feasibility, acceptability, and preliminary efficacy of individually tailored physical activity print interventions among Latinas. Although more research is needed to corroborate these findings, such high-reach, low-cost approaches have great potential to positively affect public health. Trial registration: NCT00724165. © 2009 American Journal of Preventive Medicine.