Objective: Several tools have been introduced to evaluate the quality of prescribing. The aim of this study was to determine the quality of prescribing in hypertension and bronchial asthma in tertiary health care (THC) setting using the new Prescription Quality Index (PQI) tool and to assess the reliability of this tool. Methods: A prospective cross-sectional study was carried out for 2 months in order to assess the quality of prescribing of antihypertensive and antiasthmatic drugs using recently described PQI at THC facility. Patients with hypertension and bronchial asthma, attending out-patient departments of internal medicine and pulmonary medicine respectively for at least 3 months were included. Complete medical history and prescriptions received were noted. Total and criteria wise PQI scores were derived for each prescription. Prescriptions were categorized as poor, medium and high quality based on total PQI scores. Results: A total of 222 patients were included. Mean age was 56 ± 15.1 years (range 4–87 years) with 67 (30.2%) patients above 65 years of age. Mean total PQI score was 32.1 ± 5.1. Of 222 prescriptions, 103 (46.4%) prescriptions were of high quality with PQI score ≥34. Quality of prescribing did not differ between hypertension and bronchial asthma (P > 0.05).The value of Cronbach’s α for the entire 22 criteria of PQI was 0.71. Conclusion: As evaluated by PQI tool, the quality of prescribing for hypertension and bronchial asthma is good in about 47% of prescriptions at THC facility. PQI is valid for measuring prescribing quality in these chronic diseases in Indian setting.