The Egen Klassifikation Scale version 2 (EK2) is an important functional ability assessment scale for nonambulant neuromuscular patients. We investigated the validity and reliability of the EK2 scale in Turkish Duchenne muscular dystrophy (DMD) and spinal muscular atrophy (SMA) patients. Forty-one patients were included in the study. An intra/interobserver reliability study of the EK2 scale as translated into Turkish was performed. The Brooke Functional Classification Scale (BFC) for Upper and Lower Extremities, 10-item Modified Barthel's Index for Activities of Daily Living (MBI), and Pulmonary Dysfunction Index (PDI) were used to investigate the validity of the Turkish version of the EK2 scale. Cronbach's alpha was 0.81 and ICC was 0.87 with a 95% confidence interval (r=0.92, p<0.01). There were positive, moderate correlations between the EK2 sum score and the BFC upper extremity level and between the EK2 sum score and the PDI, and a negative, moderate correlation between the EK2 sum score and the MBI (p=0.01). The Turkish version of the EK2 scale was found to be highly reliable and valid.