The area determination is basic subject in Cartography, Geography, as well as, the surface measure to foliate it is indispensable parameter in the physiologic, biogeography and agronomic investigations, in the most different vegetable species, for determination or estimate of the surface photosynthesis activates, perspiration rate, growth capacity or of production among others. The present work was developed in Fundação Faculdade de Agronomia "Luiz Meneghel" in Bandeirantes, Paraná and had as objectives to analyze the methods of leaf area determination and to identify the best method adapts to the field conditions, without the sacrifice of leaves or plants of the cultivate on the "carioquinha" bean cultivar (Phaseolus vulgarisLinnaeus, 1753). Worked with the methods of the planimeter, small square, gravimetric, co-ordinates, leaf integrator (leaflet in natura), leaf integrator (leaflet in photostatic copy), circumscribed ellipse and circumscribed rectangle. Verified that there was not significant different among the used methods and in the field conditions, the methods of the circumscribed ellipse and circumscribed rectangle are efficient for the evaluation of the leaf area of the culture on the "carioquinha" bean cultivate (Phaseolus vulgaris L.).