A new simple, sensitive and selective reversed phase precolumn fluorescence labelling method was developed for determination of sodium valproate (Na-VLP) in bulk, tablet dosage form and human plasma. The method is based on the reaction of carboxylic group containing drug Na-VLP using a new reagent 9-chloromethyl anthracene (9- CMA) producing a fluorescent product emitting at λem 413 nm after excitation at 365 nm. The derivatization reaction was carried out at 78 °C for 40 min in presence of tetrabutylammonium bromide (TBABr) as catalyst. The fluorescent products were separated on Inertsil® ODS.3 (250 mm × 4.6 mm, particle size: 5 μm) reversed phase column using ethanol and water (85:15, v/v) as mobile phase, at a flow rate of 1.0 mL.min−1. Benzoic acid was used as internal standard. The method was validated according to ICH guidelines and show good linearity over the concentration range of (0.25–20) μg.mL−1. The proposed method was successfully applied for determination of Na-VLP in tablet dosage form with no interference from excipients, the mean % recovery was found to be 100.898% ± 0.561. Furthermore, the method was also successfully applied for determination of Na-VLP in spiked human plasma without any interference from plasma matrix with mean % recovery of 100.402% ± 0.847.