In the realm of ASP.NET technology NULL pertains to the absence of a value in a variable or an object. In C# which is commonly used in ASP.NET development NULL is used to represent a reference that does not refer to an object. This means the variable has not been assigned a value or does not point to any object in memory. For instance when working with database operations in ASP.NET a NULL value could indicate the absence of data in a particular field of a database record. Here's an example in C#: string myString = null; In this example the variable myString is assigned a NULL value indicating that it does not currently point to any specific string object. In ASP.NET development handling NULL values is crucial especially when working with databases and retrieving records. It's common to use conditional statements to check for NULL values to avoid potential errors or unexpected behavior in the application. Overall understanding and effectively handling NULL values is integral to writing robust and reliable ASP.NET applications.