Parallel bit test circuits for use in a semiconductor memory devices are provided which include a first bus that has N bus lines that are configured to transfer a first group of N bits of test result data and a second bus that has N bus lines that are configured to transfer a second group of N bits of test result data. These parallel bit test circuits further include a switching unit that has a plurality of unit switches, where each switch is configured to connect a bus line of the first bus and a respective bus line of the second bus in response to a switching control signal that is applied after the second group of N bits of test result data are output from the second bus, to transfer the first group of N bits of test result data from the first bus to the second bus so as to output a total of 2N bits of test result data through the second bus.