The majority of monoclonal gammopathy of undetermined significance (MGUS) are benign forms that require no treatment but can be considered as a pre-cancerous state. Monoclonal gammopathy of undetermined significance is quite frequent, and related to age. The risk of progression to multiple myeloma or another type of malignant lymphoproliferation is estimated at 1% per year. Monoclonal gammopathy of undetermined significance is twice as frequent in patients of African descent, and prevalence is higher for men. Diagnosis of MGUS is made on evidence of a monoclonal component < 30 g/L and no CRAB criteria (hypercalcaemia, renal insufficiency, anaemia, bone lesions). Regular monitoring is required for all MGUS because they can develop into other lymphoproliferative disorders such as multiple myeloma and lymphoma and other haematologic malignancies. In view of the genetic, insular and environmental context specificities of Caribbean populations of African descent, and according to haemophilia trends of the French West Indies cancer registry, it will be interesting to determine incidence and prevalence of MGUS in a country in the Caribbean. No such study has been performed to date. There is a hypothesis for a possible geographic distribution of these blood disorders linked to environmental exposure to pesticides. The expected findings and their potential repercussions will have major public health interest, and should form the basis for a wider prognostic study to determine risk factors for MGUS in the French Caribbean. In a real life exhaustive study, the Martinique Cancer Registry proposes an epidemiological focus on MGUS in Martinique.