Early surgical outcomes after repair of atrioventricular septal defects have improved significantly over the last 60 years. Preservation of function of the left atrioventricular valve is of significant importance to achieve long-term results. For nearly 40 years, the classic, single-patch technique, as first described by Mayo Clinic investigators, has been our preferred method for repair (of atrioventricular septal defects). The single-patch reconstruction technique (described in this manuscript article), is teachable, reproducible, and reasonably durable. Our most recent 20-year experience (1995-2014) with more than 200 such repairs, and an operative mortality rate of 2.2%, is consistent with other contemporary outcomes. Left atrioventricular valve dysfunction remains the most common late, clinically notable issue.