Objectives: Supervised exercise interventions during inpatient care are feasible. The objective was to evaluate the usability of activity trackers and centralised monitoring to conduct a home-based exercise intervention during cancer treatment. The primary endpoint and confirmatory analysis was achievement of individual goals for daily steps, compared (A) in the intervention group (IG) over time and (B) between the IG and control group (CG). Secondary endpoints included achievement of goals for active minutes and effects on motor performance and health-related quality of life (hrQoL). Methods: Forty patients treated for paediatric cancer (14.7+/-3.9 years) were included. The IG received a 6-8 week intervention during acute treatment (T1) and a 2-week intervention in transition to aftercare (T2). The CG only received the intervention at T2. Baseline tests to assess motor performance and physical activity were conducted prior to every intervention. Results: In the primary confirmatory analysis, the IG significantly improved achievement of individual step goals (p=0.04) whereas group analyses did not reveal significant differences. Achievement of active minutes remained low (p=0.23). IG scored higher in hrQoL than CG (p<0.01) and percentage of children scoring below normative value in strength tests was higher in CG. Of all participants, 94% rated the intervention as meaningful and 80% as motivational. Conclusions: Results of this study indicate that this intervention for home stays with centralised supervision is feasible and leads to increased achievement of individual step goals. Despite the positive effects on hrQoL, further strategies are needed to increase positive effects on motor performance.