Recent study revealed that muscle mass was significant determinant of mortality in patients with patients with severe acute kidney injury (AKI) requiring continuous kidney replacement therapy (CKRT). However, there is little evidence on how muscle mass affects kidney recovery in these patients. We collected 1,771 AKI patients who underwent CKRT from eight medical centers between 2006 and 2021. The skeletal muscle area (SMA) was measured from the automated software from CT images at 3rd lumbar vertebra within 15 days of CKRT initiation, and classified as normal attenuation muscle area (NAMA) and low attenuation muscle area (LAMA) according to muscle density. We used Cox proportional hazard model to investigate the effects of muscle index adjusted by height2 on kidney recovery. In addition, Fine-Gray sub-distribution hazard models were used to consider the competing risks on mortality. Patients had the average age of 65.7 years, and 60.0% were male. The average duration of dialysis was 10.7 days, and 729 patients (41.2%) were discharged from the hospital independent of dialysis. The average of SMA/height2, NAMA/height2, and LAMA/height2 were 41.16cm2, 18.98cm2, and 22.17cm2, respectively. SMA/height2 (HR 1.01, 95% CI 1.00-1.02, p=0.03) and NAMA/height2 (HR 1.02, 95%CI 1.01-1.03, p < 0.01) were associated with an increased probability of dialysis independence (DI) at discharge. In addition, while SMA/height2 was identified as a factor that increased the probability of DI, it was not associated with mortality in Fine-Gray sub-distribution hazard models. The amount of skeletal muscle mass was related to kidney recovery after AKI requiring CKRT. And muscles of normal density particularly supported these results. Furthermore, after considering mortality as a competing risk, an increase in skeletal muscle mass was associated with a higher probability of DI.