Background: There have been significant concerns about the care and treatment of people with intellectual disabilities (ID) when attending general hospitals, which have led to inquiries that highlight service and systems failures. One response has been the development of Learning Disability Liaison Nursing (LDLN) Services across the UK that aim to ensure that additional, specialist support is available for patients, their carers and general healthcare professionals. Methods: A mixed-methods study to investigate the impact of LDLN Services across four Scottish NHS boards was undertaken. In total, 323 referrals made over 18 months were analysed along with qualitative data drawn from interviews and focus groups with a sample of 85 participants including patients with ID (n = 5), carers (n = 16), primary care healthcare professionals (n = 39) and general hospital professionals (n = 19) and learning disability liaison nurses (n = 6). Results: The referral patterns to the four liaison nursing services closely matched the known health needs of adults with ID, with common admissions being due to neurological, respiratory and gastrointestinal issues. The LDLN role was seen to be complex and impacted on three key areas: (i) clinical patient care; (ii) education and practice development; and (iii) strategic organisational developments. Specific patient outcomes were linked to issues relating to capacity and consent to treatment, fostering person-centred adjustments to care, augmenting communication and the liaison nurses acting as positive role models and ambassadors for people with ID. Conclusions: The LDLN Services were valued by stakeholders by achieving person-centred outcomes. With their expert knowledge and skills, the liaison nurses had an important role in developing effective systems and processes within general hospital settings. The outcomes highlight the importance of supporting and promoting LDLN Services and the challenges in delivering the multifaceted elements of the role. There is a need to take account of the complex and multidimensional nature of the LDLN role and the possible tensions between achieving clinical outcomes, education and practice developments and organisational strategic initiatives. (Contains 1 figure and 5 tables.)