Most sniff cases are canine inspections of luggage, purses, or packages of travelers, usually triggered by a match between the suspect's behavior and a drug courier profile. A small percentage are school sniffs where canines are used in dragnet sniffs of unattended lockers, cars, or items and in sniffs of particular persons or items. While Federal courts are divided over whether airport sniffs constitute fourth amendment intrusions, the majority view is that an airport sniff is simply not a search. Opinions on school sniffs are divided among the circuits. The U.S. Supreme Court addressed the dog sniff problem in United States v. Place (1983), a typical airport sniff case. While one justice commented that canine searches did not constitute a search within the meaning of the fourth amendment, parties in the case did not address this point. The Court's comments failed to resolve several problems about canine sniffs, particularly whether even the broadest and most discriminate of sniffs would invoke the fourth amendment. Using principles formulated in Katz v. United States, analysis shows such reasoning to be flawed. The rationale that a canine sniff is not a search because of its uniquely unobstrusive nature contradicts Katz. The second rationale, that a sniff is not an inspection of the object, also has dangerous implications for search and seizure law. The ruling in Terry v. Ohio on subsearches provides an alternative. Classifying a dog sniff as a subsearch allows judicial scrutiny of its reasonableness and offers fertile grounds for the development of judicial guidelines. The article contains 100 footnotes.