Resume Question - Analyst at short equity hedge fund

Very quick question...I've been an Analyst at a long/short equity hedge fund for 3+ years. I was hired directly following my graduation from college. As I begin the search to look at other firms, is it acceptable to include some of my previous summer internships under my Professional Experience? Though I'm quite confident in my abilities and qualifications, technically I've only held one full-time position, and thus I'm unsure how much I will have to fill in on my resume, unless I include at least some of my internships (which are applicable, related finance positions).

Thanks!