The knowledge of the dental anatomy, mainly the radicular portion, is of great importance to some specialities such as the Endodonty and Periodonty. The aim of this study was to analyse the radicular morphometry of the upper first premolars, checking the average length of the roots, and also, their inclinations and the location of furcation area in bi and three radiculars. In this study were used 659 human upper first premolars belonging to Department of Morphology of the School of Dentistry of Araraquara, UNESP, Brazil. The teeth were previously selected, so only the ones with perfect roots were used. The teeth were divided in three groups: mono radiculars, bi radiculars and three radiculars. After they had been separated, some specific measurements with a Brown & Sharp digital paquimeter were done in each group. In our study we could conclude that: 1 - the upper first premolars mono radiculars presented an average radicular length higher than the bi radiculars and these ones, higher than the three radiculars; 2 - the upper first premolars bi radiculars presented an average radicular length higher for the vestibular root in relation to the palatine root, both roots presents higher inclination percentage for the distal. The furcation can be located in the middle third as well as in the apical third; 3 - the upper first premolars three radiculars present an average radicular length higher for the palatine root in relation to the vestibular roots. The radicular inclination is variable, and the distovestibular root presents higher inclination percentage for the mesial while the other roots for the distal. The furcation is located, in all the cases, at the middle third.