A method of operating a memory controller is provided. The method of operating a memory controller according to an exemplary embodiment of the present inventive concepts includes sequentially receiving, by the memory controller, first data segments each having a first size from a host, sequentially storing, by the memory controller, the first data segments in the buffer until a sum of sizes of changed data among data stored in a buffer included in the memory controller is a second size, and programming, by the memory controller, the changed data having the second size in a memory space of a non-volatile memory as a second data segment.