One of the leading legal issues decided by the Supreme Court each term, as a proportion of its total docket, is the application of the Fourth Amendment. Despite the extensive attention the Court’s Fourth Amendment jurisprudence receives in legal scholarship, there has been scant empirical research about how modern Justices have voted in Fourth Amendment cases. This Article offers several empirical analyses of the 173 cases in which the Supreme Court addressed Fourth Amendment issues between 1982 and 2015. The analyses show different voting patterns among the Justices depending upon the posture of the case and the nature of the relief sought by the litigants raising Fourth Amendment claims. The key findings are: (1) the overwhelming majority of Fourth Amendment litigants (FALs) before the Supreme Court were criminal defendants rather than civil rights plaintiffs, and the overwhelming majority of Fourth Amendment issues addressed by the Court were substantive in nature (i.e., whether the Fourth Amendment had been violated) rather than remedial in nature (e.g., whether, in a criminal prosecution, suppression of incriminating evidence was an appropriate remedy for an unconstitutional search or seizure); (2) Fourth Amendment claims succeeded in slightly less than one in four plenary-review cases, and the Court reversed the judgment of the lower courts in the vast majority of Fourth Amendment cases in which certiorari was granted; (3) FALs were much more likely to succeed in cases concerning substantive issues than remedial issues; (4) civil rights plaintiffs were slightly more likely to succeed than criminal defendants; (5) individual Justices generally voted in Fourth Amendment cases in a manner that reflected their overall ideological dispositions, yet Justices Blackmun, Scalia, and Breyer bucked this trend, resulting in more ideologically mixed voting blocs in Fourth Amendment cases than in several other divisive areas of the Court’s docket, such as abortion rights or voting rights; (6) the Court has granted more certiorari petitions filed by the government than petitions filed by FALs, and was much more likely to rule against a FAL when the Court granted the government’s petition than when it granted a FAL’s petition; and (7) the Court’s per curiam cases addressing Fourth Amendment issues generally resembled the Court’s plenary-review cases with respect to the nature of the litigants and the nature of the issues addressed, although the Court always ruled in favor of the petitioners, whether the government or FALs, in its per curiam Fourth Amendment decisions.