In this contribution, a system for motion-aware ambulatory blood pressure measurement is presented for the first time. Regular measurement of blood pressure is a key factor in controlling hypertension. However, blood pressure measurements in doctor's surgeries are random samples of a value varying during the day. 24h ambulatory blood pressure measurement systems are used to get information about blood pressure changes in the course of a day. Measurement errors can occur due to movement artifacts, wrong posture during the measurement or absence of proper rest time prior to the measurement. The presented system monitors the user's motions and postpones planned measurements if proper rest is not detected. Additionally, it detects whether the user is in the proper upright position during measurement. Both, system concept and evaluations of BP measurement as well as movement and posture detection accuracy are presented.