In this study, the combined use of an accelerometer and rate gyrosensor to identify the activity phases of the timed up-and-go test (TUG-T) was proposed. Measurements during clinical rehabilitation of hemiplegic patients have been attempted using a triaxial accelerometer to measure the activity objectively, which allows a quantitative evaluation. A waist gyrosensor is useful for measuring the postural displacement with high accuracy. By using both the accelerometer and gyrosensor signals, it was possible to detect the activity phases, which were similar to those observed by the therapists. In addition, the walking activity was extracted from the TUG-T, and the RMS value and CV from the acceleration were calculated in every walking cycle. A qualitative difference between the subjects who could walk independently and those requiring supervision was revealed.