In sugarcane crop, it is important to search for tools to assist in the agricultural management to increase the yield and minimize the costs of production. Dynamics growth models are tools that help management, supporting the analysis of making complex decisions, allowing reducing cost, time and human resources. Thus, the aim of this study was to determine the best time of planting for the sugarcane crop using the DSSAT/CANEGRO model for the region of Rio Largo, state of Alagoas, Northeastern Brazil. The crop, soil and meteorological data used in the simulations were obtained in field experiment carried out at sugarcane cropping in years 2003 and 2006. The sugarcane varieties used in the experiment was RB93509 in two crop cycles (plant crop and ratoon crop). Planting was held on October 1, 2003 and the 1st harvest (plant crop) took place on October 1, 2004 and the 2nd harvest (ratoon crop) took place on February 25, 2006. The model performance was quantified by different statistical tests (Error Model, Medium Error Quadratic Root and Determination Coefficient). The model satisfactorily simulated the ​​fresh (0.6 and 11.0%) and dry matter production (-19.2 and 18.1%), tillering (R2 = 0.69 and 0.80), plant height (0.0 and -19.1%) and leaf area index (R2 = 0.87 and 0.73). The best planting time for sugarcane crop was on October 30. However, in El Niño and La Niña years of strong intensity, the best planting time was on January 15 and September 30, respectively.