Provided are a dynamic semiconductor memory device and a memory system including the same. The dynamic semiconductor memory device includes a memory cell array including a first memory cell array block including a plurality of first dynamic memory cells connected between a plurality of first word lines and a plurality of first bit lines, a second memory cell array block including a plurality of second dynamic memory cells connected between a plurality of second word lines and a plurality of second bit lines, and a sense amplification block including a plurality of sense amplifiers configured to amplify voltages of the plurality of first bit lines and voltages of the plurality of second bit lines to a first sensing supply voltage or at least one second sensing voltage higher than the first sensing supply voltage; a temperature sensor unit configured to sense a temperature and generate a temperature sensing signal; and a voltage generator configured to generate the first sensing supply voltage or the at least one second sensing supply voltage in response to the temperature sensing signal and to apply the first sensing supply voltage or the at least one second sensing supply voltage to the memory cell array and to apply a sensing ground voltage to the memory cell array.