Background: Monoclonal gammopathy of undetermined significance (MGUS) and smouldering multiple myeloma (SMM) are premalignant stages of multiple myeloma (MM). MM is a malignancy of plasma cells, which is associated with a median overall survival of 5 to 7 years. MM accounts for approximately 10% of hematological malignancies. Patients and Methods: Descriptive analysis of data from 19 Czech centres collected in the Registry of Monoclonal Gammopathies (RMG) was performed. Results: Over the last 10 years of prospective collection of data, together with retrospectively recorded data on patients diagnosed before the registry establishment, data on 7,467 patients with either asymptomatic or symptomatic form of MM have been gathered. Validation criteria for the analysis were met by 2,506 MGUS patients, 400 SMM patients and 4,738 MM patients. The median duration of follow-up was 4.3 years in MGUS patients and 2.4 years in SMM patients. The overall risk of progression from MGUS to malignancy was 1.7% per year. The risk of progression from SMM to MM was highest in the 1st years after diagnosis: overall, this risk was 16.6% per year. The median duration of follow-up was 2.8 years in MM patients. The median overall survival from the diagnosis was 5.7 years. The median OS from treatment initiation/progression-free survival decreased from 60.5/21.0 months in the 1st line therapy to 34.3/12.4 months in the 2nd line therapy, 22.6/8.9 months in the 3rd line therapy and 13.8/5.8 months in the 4th or higher line therapies. Thanks to the availability of novel drugs for MM treatment in the Czech Republic, treatment strategies have changed dramatically over the last decade. Conclusion: RMG is a registry designated for the collection of data on diagnosis, treatment, treatment results and survival of patients with monoclonal gammopathies in the long-term follow-up. RMG is a valuable source of data from real clinical practice.