This study aims to investigate the changes at heart rate and cardiac rhythm of obese patients admitted to obesity polyclinic using rhythm holter electrocardiography (ECG). Following the ethics committee approval, 114 patients admitted to Izmir Tepecik Training and Research Hospital Obesity Polyclinic between November 2012 and February 2013 were randomly assigned and monitored by rhythm holter device. The values of average heart rate (AHR), maximum heart rate (MAXHR), minimum heart rate (MINHR) and time domain parameters as SDNN, SDANN and RMSSD were recorded and their relation with obesity parameters and laboratory findings were analyzed. While 105 (92,10%) of 114 patients were female, 9 (7,90%) of them were male and the average age was 45.82±11.39 (min:16; max:69). The AHR, MAXHR, MINHR, SDNN, SDANN and RMSSD of them were 78.01±8.41 (min:56; max:109), 136.28±17.69 (min:105; max:181), 51.64±7.11 (min:24; max:67), 140.06±44.40 (min:47; max:368,45), 151.71±87.55 (min:15.13; max:415.00), and 65.55±52.83 (min:20.85; max:402.67), respectively. Statistically significant relation was found between the age and AHR, MAXHR and SDANN (p<0.01). Significant relation in regard to waist circumference was detected with only AHR and SDNN (p<0.05). Similarly, the only significant relation in regard to body mass index was detected with MAXHR (p:0.01). A decrease in heart rate variability is associated with the risk of coronary artery disease. Heart rate variability declines along with enlarging waist circumference. In the follow up process of obese patients, waist circumference monitoring comes out to be substantial rather than the overall body weight monitoring.