The roving border patrol involves a two-step process. An initial stop of a suspicious vehicle is made in order to investigate a traveler's right to be in the United States. If probable cause is found during the questioning, a search of the vehicle is made for aliens and/or contraband. This note looks at the initial stop made by roving border patrols. Generally, the fourth amendment's reasonableness standard requires, absent a consent to search, a showing of probable cause and the issuance of a search warrant by a neutral magistrate. Border searches, however, are exempt from the usual fourth amendment requirements. In United States v. Brignoni Ponce, the Supreme Court provided guidelines for making a valid roving border patrol stop which fall below the fourth amendment standard of probable cause. These guidelines create a standard of reasonable suspicion. The Courts of Appeals have struggled to refine this standard of reasonable suspicion in individual cases. This note analyzes the Supreme Court cases applying to border patrols, pointing to the weaknesses in the articulated standards. It further analyzes the Fifth and Ninth Circuit cases, showing the inconsistencies both within and between these circuits. Future action is suggested. A total of 200 case notes are provided.