Introduction: Amyotrophic lateral sclerosis (ALS) is a fatal disease characterized by progressive degeneration of the motor neurons. It is difficult to define the severity of the clinical findings of this destructive disease owing to its rapid progression, which presents serious alterations in a short time even in the same patient. The present study was designed to evaulate the validity of the Turkish version of the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R), which has been used in various countries for measuring the functional status of ALS patients. Methods: The ALSFRS-R scores of 41 ALS patients (24 male), in any stages of illness, were simultaneously assessed by two physicians. The functional status of the patients (motor system, bulbar, and pulmonary functions) was evaluated under 12 titles. In every subtitle, the functional status was evaluated as 0 for the worst functional status and 4 for the best functional status. The mean differentials for both subtitles and global scores and the 95% confidence bounds of these means were detected. The coherence was defined as the states in which the coefficient is above 0.80 and is statistically significant Results: From the data obtained, the correlation between the two physicians was found to be statistically significant (p=0.000) in terms of the means of both subtitles and total scores. Conclusion: It was shown in the present study that in the clinical follow-up of the disease, the Turkish version of ALSFRS-R is a simple, reliable, and easily applicable. [ABSTRACT FROM AUTHOR]