Aim: To determine the causality assessment of Adverse Drug Reactions of Antipsychotics in a tertiary care hospital Methods Total 150 eligible patients were enrolled from outpatient and inpatient Department of Psychiatry, GGSMCH Faridkot by using non probability convenient sampling technique. Each enrolled patient was followed up every 15 days for a period of 6 months for monitoring of adverse drug reactions. Causality assessment of adverse drug reactions if any, was done by using suitable scales like Naranjo Algorithm and WHO UMC Causality Assessment Scale. Results Total 35 ADRs were reported in 34 patients. Most common ADRs observed were EPS and dry mouth in 6 (17.14%) patients each, followed by dizziness, sedation, weight gain and constipation in 4 (11.43%) each, nausea in 3(8.57%) each, headache, postural hypotension, somnolence and tremors were observed in 1 (2.86%) patient each. Out of 34 patients who experienced ADRs , males were 67.60 percent and females 32.40 percent . No significant association was seen among gender and adverse drug reactions (p=0.786). On average , there were 1.02 ADRs per patient. Naranjo algorithm causality assessment scale reported maximum ADRs reported fell in possible category with 57.14 percent in number, 40.00 percent were in were in probable category , 2.86 percent were in doubtful category and none were reported in definite category. WHO UMC causality assessment scale reported maximum of 45.71 percent were in possible category, 31.43 percent in probable category , 22.86 percent were in unlikely category and none were reported in unassessable, conditional and certain category . Conclusion : Awareness and early detection of ADRs will help the consulting psychiatrist to make necessary alterations in the drugs prescribed or addition of newer drugs to reduce the symptoms of ADRs . This will ultimately help to improve patient care and compliance. Keywords: adr, naranjo algorithm, who umc causality assessment scale