The "agave tequilero" (Agave tequilana Weber) is an important economic resource to Mexico; this plant is used to make tequila, an export product. Many farmers apply fertilizers to this crop without any technological basis. To evaluate plant growth and yield in a short term, with non-destructive techniques is a problem in agronomic research. In this study, NPK fertilizer treatments were evaluated with non-destructive techniques. For this purpose, total plant height; number of leaves per plant and number of leaves in the rosette were used as growth indicators. The plants used in the experiment had been under cultivation for one year and were evaluated for two years, 1987 and 1988. The highest weights of "cabeza" (harvested part of the plant) were obtained with plants cultivated for 2.5 years in the 120-80-60 treatment with 5.90 kg/plant and in the 80-00-30 treatment with 5.22 kg/plant. The control without fertilization yielded 2.36 kg/plant.