Biodata including electrocardiogram (ECG), physical activity and body temperature were monitored using a telemetry system (Data Sciences Int., USA). The system comprised transmitter devices (TA11CTA-F40), receivers (RPC-1), a data exchange matrix (20CH) and a personal computer for system configuration, control and data storage. Transmitters were surgically implanted in six young adult (200-250g) male Wistar rats under general anaesthesia (sodium pentobarbitone, 45 mg/kg ip). The transmitter devices were inserted in the peritoneal cavity and electrodes from the transmitter were arranged in Einthoven bipolar (Lead II configuration). After full recovery from surgery baseline data was collected for nine days. On day 10, three animals received a single ip injection of streptozotocin (60 mg/kg bodyweight, STZ) dissolved in citrate buffer. Age-matched controls received citrate buffer alone. Biodata were recorded for 5 minutes of every hour, 24 hours per day, during a period of 1 month. From the collected data, secondary physiological measurements were determined including the average 5-minute heart rate (HR), heart rate variability (HRV), and HRV power spectral density (PSD). In order to highlight the effect of STZ-induced diabetes, baseline day 5 and 10 days after STZ treatment were statistically compared using the paired t-test. P-values less than 0.05 were considered significant. Blood glucose was characteristically elevated in STZ-treated (376.3±24.6 mg/dl, n=3) compared to controls (80.0±4.5 mg/dl, n=3). HR during the baseline period was 353±12 beats per minute (BPM, n=6) and was significantly reduced at 10 days after STZ treatment (243±12 BPM) compared to controls (365±13 BPM). HRV during the baseline period was 25±4 BPM (n=6) and was significantly reduced at 10 days after STZ treatment (11±3 BPM) compared to controls (33±3 BPM). Activity during the baseline period was 0.92 counts per minute (CPM, n=6) and was significantly reduced at 10 days after STZ treatment (0.39±0.09 CPM) compared to controls (1.04±0.13 CPM). Body temperature during the baseline period was 37.6±0.1°C (n=6) and was significantly reduced at 10 days after STZ-treatment (36.9±0.1°C) compared to controls (37.6±0.1°C). Defective autonomic regulation of cardiac function might underlie altered HRV in short-term STZ-induced diabetic rats.