Introduction More common health complaints in institutionalized patients are insomnia and sleep disorders comparing with home-living elderly patient. The aim of this study was for analyze sleep pattern in elderly population, comparing institutionalized elderly and home-living elderly. Materials and methods Case and control study comparison between 266 elderly patients (65year older), 142 institutionalized whereas the control group was 124 patients living at home. Subjects were monitored with the Actigraph GT3x device (placed on the right wrist) 24h a day during seven consecutive days, using 1s lasted epochs. The sleep patterns of both groups have been extracted through the well known Sadeh’s algorithm and analysed by means of the U-test of Mann–Whitney (a non-parametric variant of the Student’s t-test) in order to determine the existence of statistically significant differences between the groups under analysis. Results Statistically significant differences arise only during the three last days of the week (Friday, Saturday and Sunday). The number of minutes awake (p<0.02) and the average awakening (p<0.04) are higher in the case group on both Friday and Saturday, whilst the total sleep time (p<0.03) and the largest sleep time (p<0.05) are higher in the control group on Sunday. We not found statistically significant differences during working days in the analyzed variables. Conclusion The effects of institutionalization over the sleep pattern in elderly population are only significant on weekends (Friday, Saturday and Sunday). Institutionalized subjects suffer from either less or poorer sleep than those subjects that live at home. Working days, significant differences are not observed in the sleep pattern between both groups of patients. A possible explanation for this fact stems from the disruption of the institutionalized subject’s daily routine as a consequence of both their weekend habits (activities with their families, for instance) and some variations on the schedule of the staff (on-call staff instead of regular staff, for instance). Acknowledgements Research supported by the Health Service (SACYL) of the Regional Government of Castilla y Leon in Spain.