I would suggest you to check the following help article here that explains the concepts -- basically RadChart.ItemsSource specifies the datasource you will be using for your chart (usually a list of business objects), while each SeriesMapping represents a chart series you would like to visualize and defines the series type and the relations between the business object properties and the required values for RadChart (YValue, XCategory, etc.). Also if you would like to visualize several series from different datasources, you need to use SeriesMapping.ItemsSource instead of RadChart.ItemsSource.