OBJECTIVE Clinical usefulness of monitoring haloperidol in salivary samples based on plasma:saliva correlation. METHODS Plasma and saliva samples of schizophrenic patients [N=105] were analyzed by highly sensitive reverse phase liquid chromatographic method to measure haloperidol at 240 nm using UV-PDA detector. Mobile phase consist of acetonitrile and water [50:50], pH 2.5 (0.1% acetic acid and 0.05 M KHPO(4)) at flow rate 1.4 mL/min. Method was linear over 3-200 ng/mL. RESULTS Observed therapeutic range was 5-19 ng/mL [11.66±3.97] and 17-54 ng/mL [27.52±11.51] for plasma and saliva respectively. Mean S:P was found to be 2.36. CONCLUSIONS Current study showed significantly high correlation [r=0.93, p<0.0001] between haloperidol levels in saliva and plasma with linear relationship. It is therefore concluded that monitoring of salivary concentration can be a clinically beneficial substitute. Patients showing clinical improvement [N=90] were within salivary concentration range of 17-54 ng/mL, which can be an appropriate steady state monitoring range for haloperidol in saliva.