A Google Account functions as a master Google login, made up of a single email address and password.
Although a Google Account is similar to an AdSense login, your Google Account lets you easily jump to any of your Google services that also share this login (such as Google Groups, Gmail, and Froogle). This way, once you're signed in, you stay in - no more logging in and out between multiple services.
If you are having trouble logging in to your AdSense account with your Google account, visit our login troubleshooter for more help.