Accurate measurement and assessment of Parkinson's disease (PD) tremor is important for patients, clinicians, and researchers to track changes in disease progression and the effectiveness of therapeutic interventions. This study measured resting, postural, and kinetic tremor from patient's most-affected hand with accelerometers and gyrometers; thus, the linear and rotational motions in the x, y, z directions were obtained. Data were collected when patients were both ON and OFF their anti-PD medications. A bandpass filter was applied to extract raw tremor information, and several signal processing algorithms were used to analyze the data in both time and frequency domains, including the correlations between motions in different directions. The results of medication effectiveness on PD tremor and the correlational analyses were discussed.