The term monoclonal gammopathy of undetermined significance(MGUS) indicates the presence of a monoclonal protein(M-protein) without features of multiple myeloma, Waldenstrom’s macroglobulinemia, primary amyloidosis or malignant lymphoproliferative disorders(LPD). While several guidelines on the treatment of LPD exist, many doubts and perplexities still exist on who should treat a MGUS, when and how. Even where MGUS does not require any therapy, the risk of progression to a LPD is 1% per year. This risk does not diminish over time and persists even in patients(pts) whose condition has remained stable for decades, and a prolonged follow up is, therefore, recommended. We met primary care doctors to share and agree on criteria for the management of outpatients with MGUS. Our aim is to draw up guidelines or, at least, suggestions that may help to determine which MGUS pts could be cared for by the primary care doctor and which should be followed by the hematologist. We suggest that once a MGUS is diagnosed, the primary care physician will attend patients with M-protein < 15 g/L if Ig G and pts with M-protein< 10 g/L if Ig A or Ig M, without end-organ damage and without signs and symptoms of LPD. However, a hematological evaluation is recommended for patients with M-protein Ig G > 15 g/L, or M-protein Ig A > 10 g/L, or Ig M > 10 g/L, or any M-protein with end-organ damage(not attributable to any others causes) or with signs and symptoms of LPD, or rapidly increasing M-protein(> 5 g/L per year). The term monoclonal gammopathy of undetermined significance (MGUS) indicates the presence of a monoclonal protein (M-protein) without features of multiple myeloma, Waldenstrom’s macroglobulinemia, primary amyloidosis or malignant lymphoproliferative disorders (LPD). While several guidelines on the treatment of LPD exist , many doubts and perplexities still exist on who should treat a MGUS, when and how. Even where MGUS does not require any therapy, the risk of progression to a LPD is 1% per year. This risk does not diminish over time and persists even in patients (pts) whose condition has remained stable for decades, and a prolonged follow up is, therefore, recommended. We met primary care doctors to share and agree on criteria for the management of outpatients with MGUS. Our aim is to draw up guidelines or, at least, suggestions that may help to determine which MGUS pts could be cared for by the primary care doctor and which should be followed by the hematologist. We suggest that once a MG US is diagnosed, the primary care physician will attend patients with M-protein <15 g / L if Ig G and pts with M-protein <10 g / L if Ig A or Ig M, without end-organ damage and without signs and symptoms of LPD. However, a hematological evaluation is recommended for patients with M-protein Ig G> 15 g / L, or M-protein Ig A> 10 g / L, or Ig M> 10 g / L, or any M- protein with end-organ damage (not attributable to any other causes) or with signs and symptoms of LPD, or rapidly increasing M-protein (> 5 g / L per year).