Background: Amyotrophic lateral sclerosis (ALS) is a relatively rare neurological disorder affecting upper and lower motor neurons in the brain and spinal cord with survival for 3-5 years and rarely beyond 10 years. Sleep disturbances in ALS are underreported and undertreated and there is no related data from India. This study aimed to assess the frequency of sleep disorders in patients of ALS and their determinants. Methods: Patients with definite and probable ALS as per the El Escorial criteria were recruited from May 2014 to April 2016. Functional impairment, presence of sleep specific abnormalities and anxiety and depression were assessed using standardized questionnaires. Results: Forty patients with ALS (23 male; 17 female) with their median age at presentation being 58.5 years (range 44-75 years) and the median duration of illness being 18 months (range: 4-120 months) were includedin the study. Half of the patients had poor sleep quality, which was significantly worse across all components of Pittsburgh Sleep Quality Index (PSQI) compared to controls. Sleep disorders were observed in 70%, insomnia in 65%, sleep disordered breathing/hypoventilation in 52.5% and restless legs syndrome in 5% patients. Night time awakenings attributable to symptoms associated with ALS were noted in 85%, and anxiety and depression in 57.5% patients. Excessive daytime somnolence emerged as an independent predictor for the presence of sleep disorders in ALS patients on multivariate logistic regression P = 0.043, odd's ratio (OR) 1.435; 95% confidence intervalCI (1.011-2.036). Conclusion: This is the first study from India providing insight into the presence of sleep disorders in ALS. About half of the patients of ALS had a poor sleep quality and two-thirds suffered from sleep disturbances.