1 Hematological cancers, a group of cancer sub-types that include blood- and lymph-related disorders (i.e., 2 leukemia, lymphoma, myeloma, myeloproliferative neoplasms (MPNs) and myelodysplastic syndromes (MDS), 3 account for 11% of all cancer diagnoses in the US. Chronic hematological cancer (CHC) patients (i.e., chronic 4 leukemias, low grade lymphomas, myeloma, myelodysplastic syndrome, and myeloproliferative neoplasms 5 [MPNs]) have extended disease courses that are often different from solid tumor cancers, facing chronic sleep 6 disturbances often associated with inflammation, fatigue, and emotional distress (anxiety and depression), which 7 often persist into survivorship. Medications are most commonly prescribed for cancer patients with sleep 8 disturbance; however, they often come with side effects and risk for long-term dependence. Cognitive behavioral 9 therapy for insomnia (CBT-I) is the most studied and first line of therapy for treating sleep disturbances in cancer 10 patients, but CBT-I is time-consuming, resource-intensive, and not easily accessible for all cancer patients. There 11 is a need for long-term, accessible, non-pharmacologic interventions targeting sleep in CHC patients. 12 Meditation is a safe and effective non-pharmacologic approach for improving a range of cancer-related 13 symptoms. However, meditation interventions have typically been delivered in-person, limiting uptake and 14 widespread dissemination due to patient-reported barriers. Smartphone applications (apps) are a novel 15 intervention approach for delivering meditation and address cancer patients’ barriers to participating in in-person 16 interventions (i.e., fatigue, pain, transportation, and scheduling difficulties) without the time and expertise 17 limitations of CBT-I and side effect risks from medication. Calm is a popular and highly reviewed consumer18 based smartphone app that provides an innovative, accessible and scalable platform through which to deliver 19 meditation to CHC patients. 20 We propose a double-blind RCT to determine the effectiveness of an eight-week “app-based wellness” 21 intervention (i.e., active daily meditation intervention [Calm] or the placebo health education podcast control 22 group [POD]) to reduce sleep disturbance (primary outcome), markers of inflammation (TNF-a, IL-6, IL-8, and 23 CRP) fatigue, and emotional distress (anxiety, depression) (secondary outcomes) in CHC patients. 24 Assessments will occur at baseline, post-intervention (eight weeks from baseline), and follow-up (20 weeks from 25 baseline). Participants (N=276) will be randomized to an intervention (10 min/day Calm meditation) (n=138) or 26 control (10 min/day health education podcast) group (n=138). We will remotely collect blood samples for 27 biomarker measurement. This study will fill a knowledge and rigor gap regarding the delivery of smartphone28 based meditation as an intervention for sleep and provide new data on sustained effects in CHC patients to 29 reduce sleep disturbance.