© 2016 The Author(s).Background: Caregiver burden affects the physical, psychological and emotional well-being of the caregiver. The purpose of this analysis was to describe an informal caregiver cohort (n = 81), their subjective assessment of burden and difficulties experienced as a result of providing care to people with Amyotrophic Lateral Sclerosis (ALS). Methods: Using mixed methods of data collection and analysis, we undertook a comprehensive assessment of burden and difficulties associated with informal caregiving in ALS. As part of a semi-structured interview a series of standardised measures were used to assess quality of life, psychological distress and subjective burden, and in an open-ended question caregivers were asked to identify difficult aspects of their caregiving experience. Results: The quantitative data show that psychological distress, hours of care provided and lower quality of life, were significant predictors of caregiver burden. From the qualitative data, the caregiving difficulties were thematised around managing the practicalities of the ALS condition, the emotional and psychosocial impact; limitation and restriction, and impact on relationships. Conclusions: The collection and analysis of quantitative and qualitative data better explores the complexity of caregiver burden in ALS. Understanding the components of burden and the difficulties experienced as a result of caring for someone with ALS allows for better supporting the caregiver, and assessing the impact of burden on the care recipient.