The objective of this study was to predict the CP and NDF content of Pennisetum clandestinum using near-infrared spectroscopy (NIRS).Three hundred fifty-four (n = 354) grass samples were collected from different dairy herds from northern Antioquia-Colombia, during 2015 and earlier 2016, which varied in soil types and fertility and grass growth stage and were analyzed at the Chemical Analysis and Bromatological Laboratory (certificate for ISOMEC 17025-2005) of the Universidad Nacional de Colombia at Medellin. Samples were dried to constant weight in a forced-air oven at 60°C for 48 h and then ground in a Wiley mill (1-mm sieve). Crude protein (N × 6.25) and NDF were analyzed following official methods. Content of CP ranged between 14 and 30.5%, with a mean of 23.07 ± 3.73%, and that of NDF ranged from 46.60 to 65.90%, with a mean of 56.22 ± 4.70%. Samples were randomized divided in two groups, and the first group (n = 301) was used for calibration and the second group for cross-validation (n = 40) and external validation (n = 13). Samples for calibration and cross-validation were scanned in an NIRS DS 2500 F monochromator (Foss-NIRsystem, Denmark) in the range of 1,108 to 2,492 nm for CP and 858 to 2,492 nm for NDF, with reflectance data collected every 8 nm. Modified partial least squares (MPLS) regression was applied to scatter-corrected spectra (SNV and detrend) and mathematical treatment (equation generation) was performed in the software WinISI version 4.8. The equations were selected by evaluating the statistical parameters (R2 higher than 0.80, a SE of cross-validation [SECV] close to the SE of calibration [SEC], and a SE of reference database:SE of cross-validation [RPD] ratio greater than 3). As a result, the equation selected for CP was mathematically treated with derivative, 1; gap, 4; smooth, 3; smooth 2, 1; the mean was 22.48; SD 2,91; SEC 03253; SECV 0.439; and RPD 6.62 and correlation coefficients of calibration, cross-validation, and external validation were 0.977, 0.920, and 0.982, respectively. The equation selected for NDF was mathematically treated with derivative 1; gap, 4; smooth, 3; smooth 2, 1; the mean was 56.18; SD 4.56; SEC 1.571; SECV 1.770; RPD 2.75 and correlation coefficients of calibration, cross-validation, and external validation were 0.847, 0.727, and 0.781, respectively. According to these preliminary results, it was possible to predict reliably the CP content of P. clandestinum, but for NDF, further work is still needed.