Background: The incidence of carcinoid tumours is approximately 1.5 per 100 000 of the population. The malignant carcinoid syndrome, which is caused by circulating neuroendocrine mediators produced by the tumour, occurs in less than 10% of patients. Cutaneous involvement, although recognized in this rare syndrome, has rarely been reported. Objectives: To examine a series of patients with the malignant carcinoid syndrome, to establish the prevalence and types of cutaneous involvement and to assess whether these could be used as indicators of disease activity, progression and prognosis. Methods: Patients with the malignant carcinoid syndrome who attended a multidisciplinary clinic for neuroendocrine tumours over a 23 month period between February 2001 and December 2002 were invited to participate in the study. This involved completion of a standard history proforma and a detailed cutaneous examination with findings recorded by clinical photography. Results: Twenty- five patients were enrolled. All but one had experienced flushing, three had rosacea, five had clinical features of pellagra and two had scleroderma. Flushing was generally an early manifestation of the syndrome, whereas both the pellagra and scleroderma tended to occur in more advanced disease. Conclusions: This descriptive case series indicates that cutaneous features are not uncommon in the syndrome. They are readily diagnosed on clinical examination, and may be useful indicators of disease activity and prognosis. Background: The incidence of carcinoid tumors is approximately 1.5 per 100 000 of the population. The malignant carcinoid syndrome, which is caused by circulating neuroendocrine mediators produced by the tumor, occurs in less than 10% of patients. Cutaneous involvement, although recognized in this rare syndrome, has rarely been reported. Objectives: To examine a series of patients with the malignant carcinoid syndrome, to establish the prevalence and types of cutaneous involvement and to assess whether these could be used as indicators of disease activity, progression and prognosis. Methods : Patients with the malignant carcinoid syndrome who attended a multidisciplinary clinic for neuroendocrine tumors over a 23 month period between February 2001 and December 2002 were invited to participate in the study. This involved completion of a standard history proforma and a detailed cutaneous examination with aware recorded by clinical photography. Results: Twenty- five patients were enr olled. All but one experienced experienced flushing, three had rosacea, five had clinical features of pellagra and two had scleroderma. Flushing was generally an early manifestation of the syndrome, both both the pellagra and scleroderma tended to occur in more advanced disease. Conclusions: This descriptive case series indicates that cutaneous features are not uncommon in the syndrome. They are readily diagnosed on clinical examination, and may be useful indicators of disease activity and prognosis.