This letter aims to estimate the effective scattering albedo (ωp) over the tropical forests using L-band (1.4 GHz) microwave remote sensing. It is carried out using Soil Moisture and Ocean Salinity (SMOS) mission data over five years (2011- 2015). We find similar values of ωp computed over the Congo and Amazon forests. The ωp values depend slightly on the polarization. The values of ωp at H-polarization and at 52° ± 5° (40° ± 5°) of incidence angle are within the range 0.064 - 0.069 ± 0.015 (0.061 - 0.067 ± 0.012). At V-polarization, the values of ωp are slightly lower (0.060-0.061 ± 0.013 at 52° ± 5° of incidence angle and 0.052 - 0.055 ± 0.013 at 40° ± 5° of incidence angle). These findings should contribute to a better calibration of the value of ωp over the tropical forests in both the SMOS and SM active and passive retrieval algorithms, leading to increase the SM retrieval accuracy over heterogeneous pixels.