This case study provides an overview of our experience of conducting qualitative interviews with young people with chronic fatigue syndrome (CFS) / myalgic encephalomyelitis (ME) and co-morbid low mood. We interviewed young people with CFS/ME and low mood to gain insight into their views of the relationship between their fatigue and low mood, why they felt they developed low mood, the impact of illness on their lives, and treatment strategies they found helpful or unhelpful. In this case study we outline our methods and results, discuss our specific methodological strengths, such as including young people in research design, and illustrate the ethical issues involved in interviewing this patient group. We also describe some of the challenges we encountered, such as difficulty recruiting. Lastly, we outline some general recommendations for conducting interviews with young people (alone and with parents), and comment on some specific suggestions for mitigating the challenges we encountered.