When does Application_Start get called? I have the following code in the Application_Start function and but it does not seem to run. I would like to Flush the cache on application start up.

When I debug my program in Visual Studio shouldn't the Application_Start event run everytime I debug???

Application_Start event runs only once when the application first time runs.

It run again whenever the application restarts, like change in webconfig etc.

Check the link below

Understanding Global.asax

HC

As the others mentioned, Application_Start is called when the application is first started or, more specifically, when the application receives the first request. Typically, this only happens once, but there are some events which may require the application to restart, such as a change to the web.config file, as mentioned before. To answer your second question, yes, the event is fired before you even get to the UI of the app. If you're not seeing this behavior, make sure your breakpoints are setup appropriately.