The production of microalgae biomass appears as a promising alternative in obtaining raw material for the production of biofuels. One of the main factors influencing the growth of microalgae is light, so, microalgae culture systems must ensure the necessary irradiance to the cells in order to ensure the growth and synthesis of carbohydrates by microalgae. In this sense, the objective of this work was to evaluate the influence of different fluid heights, in raceways type tanks, and different initial cell concentrations in the accumulation of carbohydrates by the Spirulina platensis microalgae. Spirulina platensis LEB 52 microalgae was cultured with 20% Zarrouk medium. Heights were tested of 10 cm and 20 cm and initial cell concentrations of 0.10 g.L -1 and 0.20 g.L -1. The trials with the lowest tested heights, 10 cm, presented a higher cell growth, while the highest tested heights, 20 cm, and a higher initial cell concentration, 0.20 g.L-1, provided a greater accumulation of carbohydrates.