Disclosed are a memory device and a data decision method. The memory device may include a memory cell array, and a decision unit configured to read first data from the memory cell array via a first channel, perform at least one of a hard and soft decision on the first data using a first number of decision levels set based on characteristics of the first channel, read second data from the memory cell array via a second channel, and perform a soft decision on the second data using a second number of decision levels set based on characteristics of the second channel.