Introduction: Data envelopment analysis is an operational research-based method for estimating the efficiency of the general execution of hierarchical units of hospital considering the availability of various data sources in form of inputs and outputs. Objective: This research focuses on analyzing operational efficiency and finding slack in the input of tertiary hospitals of Punjab. Demand for health services is increasing but the availability of health services are still a big issue. In the present circumstance, it has turned out to be difficult for hospitals in Punjab to guarantee increasingly productive methods for administrations. Under the current conditions, it is fundamental to discover the fitting asset blend and its use. Methods: VRS-DEA model of data envelopment analysis is applied on data collected from 1st January 2018to 31st December 2018 for hospitals inputs and outputs to analyze efficiency and find slack of 48 tertiary hospitals of Punjab of three different sizes toward to output. Results: This research indicates that smaller hospitals have an efficiency more than large size and mid-size hospitals as smaller size hospitals average efficiency is .80. The mean efficiency of medium size hospitals is .75and large hospital is .71. Only 4hos petals are working at the constant return to scale and working efficiently and 44 are inefficient as these 44 hospitals are suffering huge slack in Inputs. Mean Slack of 27.31%, 18.5%, 9.5%observed in large size, Medium size and small size hospitals in the number of patients attended. Conclusion: Hospital authorities must benchmark efficiency with the best performing hospitals in that area. Data envelopment analysis must be used to distinguish the hospitals on basis of efficiency and policymakers can use this as a tool to evaluate the performance of public hospitals and set key performance indicators for allocating fund to these hospitals.