Near infrared transmission spectroscopy combined with chemometrical methods can be applied for identity confirmation of double-blind clinical trial tablets. Samples of two clinical studies, investigating the dose and placebo effect of an experimental drug, were studied. The identity of the blistered tablets was checked using partial least squares beta classification (PLSBC) applied to their NIR transmission spectra. PLSBC is a new supervised classification approach based on partial least squares (PLS) regression combined with beta -error driven class boundaries. It has the ability to limit the probability for misclassification to a known number and therefore providing the method developer a tool for deciding whether the NIR spectra of the different strengths of tablets are specific enough to obtain a robust classification model. The presented approach has the advantage to be applicable on most commercial available near infrared spectroscopy (NIRS) instrumentation software and it can be applied in a GMP environment since validation according to the ICH Q2A and Q2B guidelines on analytical method validation is fast and relatively easy. (C) 2004 Elsevier B.V. All rights reserved.