Objectives: To develop and propose a cost-effective trauma care network for Karachi, Pakistan, by calculating maximum timely trauma care (TTC) coverage achieved with the addition of potential designated private and public level 1 and level 2 trauma centres (TCs). Setting: A lower middle-income country metropolis, Karachi is Pakistan\u27s largest city with a population of 16 million and a total of 56 hospitals as per government registry data. Participants: 41 potential TCs selected using a two-level, contextually-relevant TC designation criteria adapted from various international guidelines. Primary and secondary outcome measures: Maximum TTC coverage achievable with the addition of potential TCs. Proposed trauma care network composition to achieve maximum TTC coverage. Results: Coverage with five public level 1 hospitals alone is 74.4%. Marginal benefit with stepwise addition of five potential private level 1 TCs, four public level 2 TCs and two private level 2 TCs is 12.2%, 7.1% and 3.1%, respectively. Maximum possible TTC coverage is 96.7%. Poorest coverage with the proposed 16 hospital network is noted in Malir district while 100% coverage is achieved in the centrally located South, Central and East districts. Conclusion: Addition of private level 1 and private and public level 2 hospitals to the trauma care network is necessary. Implementation of the proposed trauma care network requires strong stewardship from the government and coordinated effort of multiple stakeholders is needed to ensure standard TC designation. The study exhibits an effective method to scientifically plan and develop a cost-effective trauma system which can be applied in other resource-limited geographical area