Background; The Registry of Monoclonal Gammopathies (RMG) was established by the Czech Myeloma Group in 2007. RMG is a registry designed for the collection of clinical data concerning diagnosis, treatment, treatment results and survival of patients with monoclonal gammopathies. Data on patients with monoclonal gammopathy of undetermined significance (MGUS), Waldenstrom macroglobulinaemia (WM), multiple myeloma (MM) or primary AL ("amyloid light-chain*) amyloidosis are collected in the registry. Data: Nineteen Czech centres and four Slovak centres currently contribute to the registry. The registry currently contains records on more than 5,000 patients with MM, almost 3,000 patients with MGUS, 170 patients with WM and 26 patients with primary AL amyloidosis, Le. more than 8,000 records on patients with monoclonal gammopathies altogether. fl«sufts;Thts paper describes technology employed for the collection, storage and subsequent online visualisation of data. The CLADE-tS platform is introduced as a new system for the collection and storage of data from the registry. The form structure and functions of the new system are described for all diagnoses in general; these functions facilitate data entry to the registry and minimise the error rate in data. Publicly available online visualisations of data on patients with MGUS, WM, MM or primary AL amyloidosis from all Czech or Slovak centres are introduced, together with authenticated visualisations of data on patients with MM from selected centres. Conclusion: The RMG represents a data basis that makes it possible to monitor the disease course in patients with monoclonal gammopathies on the population level.