Systematic Review: Chronic pain and insomnia are highly comorbid, and evidence suggests a reciprocal relationship between these. CBT-I has been shown to improve sleep in those with chronic pain, therefore the potential of improved sleep leading to improvements in pain symptoms is a possibility. This led to the question: Does CBT-I improve pain symptoms in those with chronic pain and insomnia? A systematic review of the literature was conducted resulting in eight papers regarding six studies. Evidence was moderate that CBT-I improved sleep and pain related disability, but did not improve self reported pain levels. This discrepancy between improvements in pain related disability and no changes in self-reported pain levels led to the research question for the empirical element of the current thesis. Empirical Element of Thesis Objective: Chronic low back pain (CLBP) is a common form of chronic pain that affects a large population each year. Chronic pain and insomnia are highly comorbid conditions, yet knowledge about how patients perceive their interaction is limited. This qualitative study aims to inform our understanding of the patient experience with particular reference to beliefs and attributions surrounding pain, poor sleep and their interaction. Methods: 11 outpatients from a chronic pain clinic were recruited who suffered CLBP as their main symptom, and who had subsequently developed insomnia as a result. Data were analysed using Interpretative Phenomenological Analysis (IPA). Results: Qualitative analysis produced five super-ordinate themes: 1) the privacy of pain and solitude of sleep; 2) sleep/pain interaction; 3) night-time thinking; 4) adjustment and acceptance; and 5) self-management. Discussion: The first three themes combine to create the individual experience of CLBP: the visceral, emotional experience; the pre-existing and shifting beliefs; and the thought content. Once this is in place, the individual can reflect on what this means to them, and through acceptance, move through to adjustment. The individual accepts elements of their current experience, but where they see the opportunity to take control, these adjustments are translated into actions relating to self-management. These themes suggest CBT-I should be adapted to include pain specific beliefs to form a CBT for Insomnia and Chronic Pain (‘CBT-CPI’).