This work was carried out to determine the maturation curve of C. juncea in function of the stalk basic density. Besides the stalk density, other agronomic and technological characteristics were determined in plants with 60, 90, 120, 150, 180, 210 and 240 days. The results showed that stalk basic density remained statistically constant after 120 days. This clearly shows that in this time the C. juncea fibers reached the maturity, take in consideration the region of Campinas (SP). Other characteristics (height and diameter of the plant, ash percentage, total sugar, liber percentage, cellulose yield and fibers dimensions) remained practically constant with the plant development.