The determination of cefaclor in a new, complex chocolate matrix was performed by using a simple sample preparation (dispersion in dilute hydrochloric acid at 80 degrees C, centrifugation, washing with cyclohexane), followed by ion pair HPLC on a Kinetex pentafluorophenyl core-shell stationary phase with UV detection at 265 nm. We obtained good linearity (R2 = 0.9976) and precision (average RSD 0.86%) for the relevant concentration range. The preparations, although hand-made in this pilot phase, showed good uniformity of content. After being stored for four weeks in a refrigerator the preparation did not contain recognizable amounts of decomposition products.