A training method for a memory device includes providing, at a memory controller, a clock signal to the memory device to synchronize a control signal at a reference time point of the clock signal. When the clock signal, such as a training clock signal, does not transition after the reference time point, a failure time point is found at which the memory device fails to sample the control signal at the reference time point, based on the clock signal and the control signal. A synchronization time point of the control signal may be set, at which the memory device secures a sampling margin for sampling the control signal at the reference time point, based on the failure time point. A sampler circuit may sample the control signal at an edge of a rising edge of the clock signal.