A method of programming a nonvolatile memory device comprises applying at least one test program pulse to selected memory cells located in a scan read area, performing a scan read operation on the selected memory cells following application of the at least one test program pulse to detect at least one one-shot upper cell, calculating an offset voltage corresponding to a scan read region at which the scan read operation is performed, setting a program start bias using the offset voltage, and executing at least one program loop using the program start bias.