Background: Physical inactivity is a global issue for cancer survivors. Wearable trackers are promising to address physical inactivity by providing real-time feedback on physical activity (PA) and offer opportunities for self-monitoring and goal setting. Meta-analysis has reported the effects of interventions that incorporate wearable trackers on improved physical inactivity and related health outcomes (e.g., BMI, anxiety and depression, and self-rated health). However, wearable trackers were often used an an adjunct to PA interventions, and the effectiveness of wearable trackers alone is unknown. The aim of this study was to determine the association of wearable trackers with PA and health outcomes (BMI, anxiety and depression, and self-rated health) in patients with cancer, using a national dataset. Methods: Data from 957 cancer survivors from Health Information National Trends Survey – Surveillance, Epidemiology, and End Results Program (HINTS-SEER-2021) were analyzed. The outcome variables examined were: time spent in moderate to vigorous physical activity (MVPA), weekly frequency of strength training, BMI, anxiety/depression levels, and self-assessed health status. The primary independent variable was whether cancer survivors had used wearable devices within the past 12 months. Design-based linear regression for continuous outcome variables and ordinal logistic regression for ordinal outcome variables were conducted to determine the associations, after controlling for sociodemographic, cancer-related clinical (i.e., type, stage, time since diagnosis), and general health-related factors (i.e., BMI and smoking). All data analyses accounted for the complex survey design and sample weights. Results: Only 28% of cancer survivors reported wearable devices use. Bivariate analyses showed younger age, higher income, and employed status were significantly associated with wearable tracker use (P<.001). Wearable devices use was significantly associated with higher time spent in MVPA (b=37.94, 95% OR:8.38, 67.5; P=.01), more frequent strength training per week (adjusted OR=1.50, 95% OR: 1.09, 2.06; P=.01), and better self-rated health status (adjusted OR=1.58, 95% OR:1.09, 2.29; P=.01), but not associated with BMI or anxiety/depression. Conclusions: This study suggests that the uptake of wearable devices is low and highlights the digital divide among patients with cancer. This study has confirmed the associations of wearable tracker use with PA and self-rated health, supporting using wearable trackers as a promising tool to facilitate PA promotion.