ABSTRACT The merger of Housing Development Finance Corporation Limited (HDFC Ltd.) with HDFC Bank Limited, effective from 1 July 2023, marked one of the largest mergers in the Indian banking sector. This study analyses the financial performance of HDFC Bank before and after the merger by comparing the pre-merger and post-merger periods from FY2021 to FY2025. The study uses secondary data collected from HDFC Bank Annual Reports, RBI publications, NSE, BSE, and other reliable financial sources. Financial performance is evaluated using key indicators such as Return on Assets (ROA), Return on Equity (ROE), Earnings per Share (EPS), Credit–Deposit Ratio, Net Profit Growth Rate, and descriptive statistical tools. The findings reveal that the merger positively impacted HDFC Bank's overall financial performance. EPS, Credit–Deposit Ratio, Net Profit, and lending capacity improved after the merger, while ROA and ROE experienced only a slight decline due to the increased asset and equity base. Overall, the study concludes that the merger strengthened HDFC Bank's financial position, improved operational efficiency, and supported sustainable long-term growth and shareholder value. Keywords: HDFC Bank, HDFC Ltd, Merger, Financial Performance, Pre-Merger Analysis, Post Merger Analysis, Ratio Analysis, Descriptive Statistics, Profitability, Banking Sector