Background and Objectives There is limited access to specialized mental health care in countries such as India with a wide treatment gap for psychiatric illnesses. Integrating mental health delivery with primary health-care services is vital. The clinical schedules for primary care psychiatry (CSP) was designed for training primary care doctors (PCDs) to identify and diagnose psychiatric illness in patients presenting to primary care settings. This study aims to study the validity and reliability of the CSP and its hypothesis is that the CSP would help PCDs to identify psychiatric caseness. Methods The study was conducted at three primary health centers of Karnataka. Consented PCDs were briefly trained in the use of CSP and screened patients who were later interviewed by a psychiatrist using a semistructured interview and confirmed by International Statistical Classification of Diseases and Related Health Problems 10th edition (ICD-10) symptom checklist. The appropriate statistical analysis was performed. Results A total of 180 patients were included. Agreement was found between diagnoses made by PCDs and psychiatrist for 142 (78. 9%) patients with a Cohen's kappsychiatry pa (K) = 0. 57. The sensitivity was 91. 1% and specificity was 68. 3%. The interrater reliability showed K = 0. 7. Conclusion The CSP helps PCDs to make psychiatric diagnoses. It has a relatively high sensitivity with reasonably high specificity but mayneed clinical training.