Background: Previous studies on the relationship between SLEEP PATTERNs and obesity in the elderly are limited and have conflicting results. Moreover, few studies have measured SLEEP PATTERNs objectively. In this study, we investigated objective SLEEP PATTERNs and their relationship with obesity in the elderly in Tehran, Iran. Methods: In this cross-sectional study, 88 elderly (≥ 60 years old) who were members of health homes of zone 5 in Tehran, Iran, were included by simple random sampling method in 2014. SLEEP PATTERNs were objectively assessed using waist actigraphy for a mean of 4. 3 ± 1. 7 days). Height, weight, and waist circumference (WC) were measured by standard methods and body mass index (BMI) was calculated. Data entry and statistical analyses were performed using SPSS version 21. Results: Mean actigraphy-assessed SLEEP duration, SLEEP efficiency (percentage of time in bed spent SLEEPing), and SLEEP latency (time required to fall aSLEEP) were 427 ± 62 min, 71. 3 ± 18%, and 14. 2 ± 3. 8 min, respectively. A negative relationship was found between BMI and SLEEP duration (r = − 0. 2, p = 0. 03), BMI and SLEEP efficiency (r = − 0. 3, p=0. 01), and WC and SLEEP efficiency (r = − 0. 2, p = 0. 04). Also, a positive association was observed between BMI and SLEEP latency (r = 0. 4, p = 0. 006). Conclusions: In the elderly, actigraphy-assessed SLEEP duration was associated with obesity and the SLEEP efficiency was poor in obese participants. It seems that SLEEP PATTERNs and BMI are correlated with each other. However, there is a need for prospective studies to affirm causal relationships between these constructs.