© 2014 Asia-Pacific Signal and Information Processing Ass. A telemetry system for the measurement of heart rate variability (HRV) has been developed with a low-cost manufacturing process and a low-power consumption design. All the components and functions for the RRI measurement were implemented on a wearable telemeter which can operate for up to 10 hours with a rechargeable Li-Polymer battery, and the RRI data is stored into a smartphone via a Bluetooth wireless transmission. In a long-term measurement of a young subject that extended over 48 hours in total, the results showed a 1% probability of recurring errors. The obtained results suggest that the proposed fully-wearable system enables the continuous monitoring of HRV for both clinical care and healthcare operated by a non-expert.