In this paper, the influence of the doping level at boron doped nanocrystalline diamond (BDND) films in the electrochemical determination of nitrite was reported. The morphology and the structure modifications as function of the boron doping level increase were observed. Two different doping levels were considered. A BDND film with a doping level of 30.000 ppm and one another with a doping level of 10.000 ppm was used. The columnar growth for the 30.000 ppm BDND led to a higher surface roughness and also to a greater grain size when compared to that 10.000 ppm BDND. The Raman spectra shown higher sp2-bonded carbon amount in grain boundary for the 10.000 ppm BDND film due to decrease of the grain size. The morphological and structural modifications of the BDND films were crucial for nitrite oxidation process. The 30.000 ppm BDND electrode presented a better sensitivity to the nitrite oxidation and a lower detection limit (DL) on the “as-grown” condition, while the 10.000 ppm BDND electrode presented a better analytical sensitivity and a lower DL after the surface pre-treatment with hydrogen plasma.