You can declare the Microbiology major at any time in your undergraduate career. You should initially meet with the Student Services Coordinator (Katy France, go.wisc.edu/v59409) to discuss the major, the science, and to make a tentative 'road map' for the remainder of your time here at UW-Madison. The department encourages you to schedule that meeting as early as possible, for a couple important reasons. Once declared, you will receive emails from the Student Services Coordinator containing information on course offerings, academic announcements, job postings, career preparation activities/events, graduate and professional school preparation information, and more. Additionally, when you become a Microbiology major, you will be assigned an advisor from the department. You should plan to meet with your advisor each semester.