Background: Cognitive impairment is prevalent in hematologic cancer survivors treated with BMT. There is a need for remote, accessible, and engaging interventions in order to mitigate adverse cognitive outcomes following treatment. We report on feasibility, satisfaction and preliminary efficacy of a remote cognitive training intervention in BMT survivors. Methods: Participants enrolled in the cTAG study were randomized to either using the online brain games Lumosity program daily for 12 weeks, or the waitlist arm. Cognitive function was assessed using a comprehensive battery covering executive function, processing speed, attention, memory and learning domains, and PROMIS Short Form4a for cognitive complaints. Participants’ satisfaction was measured using an exit survey. Standardized T-scores (mean: 50; standard deviation: 10), were used for domain-specific outcomes. An intention-to-treat analysis was used to model the change in cognition at 12 weeks compared to baseline, between study arms, controlling for baseline cognitive reserve, age, sex and race/ethnicity to enhance estimate precision. Results: Feasibility: 150 eligible patients were approached, 88 (58.7%) consented and 71 (80.7%) were randomized. Fifty-five patients completed the study (28 on active and 27 on waitlist arm). Post-randomization attrition rate was 19.7%. Median age at time of test was 58y (range: 27-74); 60% males, 83.6% Non-Hispanic White and 16.4% non-Hispanic Black, and 49% with low cognitive reserve. There were no significant differences between study arms. Adherence on active arm: Median of 87.5% for 4.9 days/week and 10/12 weeks. Preliminary Efficacy: Compared to the waitlist arm, scores improved for the active arm in attention (2.14 points, SE=1.01, p-value=0.039) and memory domains (5.63, SE=2.40, p-value=0.02). There was no significant change on cognitive complaints between the two arms. Satisfaction: Overall 78.2% of patients had no prior experience with cognitive training, 58.7% felt it helped their recovery, 82.6% found time commitment reasonable, 87% found it easy to follow, fun, engaging and appropriately challenging. The intervention had a 91.3% satisfaction rate; 73.9% indicating they would continue training and 87% would recommend it to others. Participants’ perceived benefit from training was highest for attention (89.1%), memory (73.9%), and visual tasks (69.6%). Only 11% of participants perceived benefits for real word tasks. Conclusions: The intervention was feasible, favorably rated, and associated with both perceived and objective improvements in attention and memory domains. Remote cognitive training carries several advantages for BMT patients including early and convenient at home administration supporting its clinical utility and potential long-term adoption following treatment. Clinical trial information: NCT03094026.