Levels of the anticonvulsant drugs phenobarbitone, phenytoin, carbamazepine, and primidone were measured in the plasma and saliva of 202 epileptic children (5 months-18 years old). Gas-liquid chromatography (GLC) and EMIT® immunoassay were used to analyse the samples. Saliva to plasma ratios were as follows (means ± SD). phenobarbitone: GLC, 0.30 ± 0.05 (r= 0.94); EMIT, 0.31 ± 0.06 (r= 0.92); phenytoin: GLC, 0.11 ± 0.02 (r= 0.94); EMIT, 0.12 ± 0.04 (r= 0.86); carbamazepine: GLC, 0.26 ± 0.05 (r= 0.91); EMIT, 0.25 ± 0.06 (r= 0.83); primidone: GLC, 1.04 ± 0.24 (r= 0.94); EMIT, 0.95 ± 0.20 (r= 0.98). There was good agreement between the two methods, and the ratios obtained are the same as those found for adults.