To cusomize data point label density in an RDLC, you have to open the RDLC first in Visual Studio 2008. I have attached the sample file, that contains the RDLC of a line chart, feel free to use it for your projects! (its on the bottom of the post, CUSUM.zip) After opening the RDLC report, right click on the line chart, and select Properties. Click on Point Labels on the top. Here you can modify the value in the fuction. By default its 3, meaning it will put out point label for every third data point. If you want to take a look at the function itself, go to back to the main screen of Visual Studio, select Report -> Report properties in the menu bar. Here go to the "Code" tab. The function is called "Szamol". You can embed it to your own RDLCs too if you wish to use it for a different chart!