Service quality has become a major concern for both the hospitals and the patients. The increase in competition coupled with the increased patients’ perception of service quality makes it difficult for hospitals to provide services that meet patient satisfaction. Recognition of the importance of service quality is the need of the hour in order to provide better services to the patients. The objectives of the present study are to identify the critical factors of inpatient service quality in a hospital and to develop the HospitalQual theoretical model to measure inpatient service quality. The present study was explorative and descriptive in its nature. An empirical study was conducted in a public hospital located in Hyderabad, India. The data was collected through a self administered questionnaire from 246 in-patients with a purposive sampling technique. The statistical techniques such as factor analysis and the multiple regression were used in the data analysis. The study has identified the factors to measure the inpatient service quality and developed a comprehensive instrument i.e. “HospitalQual” with seven dimensions, namely; medical, nursing, support, administrative services, patient safety, communication and hospital infrastructure. In addition, the supportive services are found to be the most important factor to predict the overall inpatient service quality, followed by nursing services, administrative services, medical services, patient communication patient safety and hospital infrastructure. The application of HospitalQual would help to identify the gaps in each of the dimensions over a period of time and enable hospital administrators to monitor, control and improve the inpatient service quality in a hospital.