The use of computer-supported near-IR reflectance spectroscopy (NIRS) for quality control monitoring of powder mixts. contg. components in the % range is demonstrated, with a mixt. of pharmaceuticals (acetylsalicylic acid, paracetamol, and caffeine) as an example. Although not suitable for trace anal. (detection limit of approx. 1 wt. %), NIRS is shown effective in the quant. anal. of powders, with, for the example quoted, variation coeffs. of 0.5-1%, comparable to those from UV spectroscopy or chromatog. Sample history and treatment must be controlled, however, to avoid spurious effects resulting from powder size distribution or geometry changes.