In an important article in the Yale Law Journal, James Pfander and Daniel Birk claim that adverseness is not required by Article III for cases arising under federal law. This Article takes the position that Pfander and Birk have not made the case for reconsidering adversity requirements for Article III cases. Adverseness may be present when there is adversity of legal interests, even when adverse argument is not present. From this perspective, a number of Pfander and Birk’s examples of non-contentious jurisdiction manifested adverseness. In rem-type proceedings such as bankruptcy and prize cases required the determination of adverse interests, in situations where impediments often existed to voluntary extrajudicial resolution. Service or notice in some form was generally provided, which gave opportunities for adverse argument. In addition, the issuance of warrants, while ex parte, involved adverse interests in a context where predeprivation notice would undermine the utility of the proceeding, notice occurred on execution of the warrant, and opportunity for argument was then often available. Pfander and Birk’s examples of pension and naturalization determinations are not as readily characterized as adverse. The Court, however, treated federal judges’ pension determinations as appropriate, if at all, as the work of individual commissioners rather than Article III judges. Naturalization petitions are perhaps Pfander and Birk’s best example of non-contentious jurisdiction, but the Court explicitly approved the practice as appropriate under Article III only after provisions for notice to, and potential appearance by, the United States.