A method using high-performance thin-layer chromatography (HPTLC) for quantitation of sertraline in human serum was developed and validated. It includes a liquid-liquid extraction with diethyl ether-chlorophorm (75:25, v/v) and carbamazepine as internal standard. Chromatographic separation was performed on precoated silica gel F-254 HPTLC plates using a mixture of toluene-ethyl acetate-methanol-glacial acetic acid (4.5:1.5:1.0:0.5, v/v) as mobile phase. The method showed good relationship (r = 0.998) (1.00-70.00 ng/band, corresponding to 0.01 and 0.70 ng/mu L in serum after extraction process and applying 10 mu L to the chromatographic plates). This range includes serum concentration found in literature (0.02-0.50 ng/mu L). The % RSD values of intra- and inter-assay were between 0.88-2.75 and 0.76-3.36, respectively. The limit of detection and the limit of quantification were 0.12 and 0.25 ng/band. The accuracy values were between 94.65% and 98.93%. R-F for N-desmethylsertraline or norsertraline (major metabolite of sertraline), sertraline, and carbamazepine were 0.23, 0.45, and 0.71, respectively. Ten samples of patient volunteers who were using sertraline as a treatment for major depression were analyzed using the method developed and found sertraline concentrations between 0.05 and 0.32 ng/mu L. In conclusion, the method is precise, accurate, selective, and sensitive for quantitative determination of sertraline in human serum, and it could be used for pharmacotherapy adherence evaluation.