Economic corridors have gained popularity as a potentially important instrument in the development and transformation of low and middle income economies. But why have some countries had more success with them than others? What role does governance, institutions, finance and policy frameworks play in determining their success? How can we measure their impacts? We try and answer these questions by looking closely at, and drawing lessons from, two case studies of successful corridors in Asia, Malaysia and Thailand. A key conclusion is that economic corridors are more likely to succeed with greater domestic spillovers when the physical and policy infrastructure are conducive.