Objectives: Prior studies have examined sleep during the COVID-19 pandemic, but have few compared sleep measured both during and prior to COVID. We examined the impact of the COVID-19 pandemic on subjective sleep quality in general and separately by gender and age (<50 vs ≥50 years). Further, we compared sleep quality between those who did and did not follow quarantine orders.Methods: This sample is from the Baependi Heart Study, a family-based cohort of adults in South- eastern Brazil. Longitudinal data were from 417 individuals who completed the Pittsburgh Sleep Quality Index (PSQI) twice: between January 2010 and September 2014 (pre-COVID) and during the COVID-19 stay-at-home order March-June, 2020. Cross-sectional analysis included 800 participants. Results: Mean (±SD) PSQI scores were significantly higher during than before COVID-19 (5.7 ±3.8 vs 5.0 ±3.3, p<0.01). This increase was significant among women and among adults ≥50 years but not in men or younger adults. The significant increase in PSQI was only observed in those who quarantined during COVID-19 (5.9 ±3.7 vs 5.2 ±3.4, p<0.01) and not those who did not quarantine (5.0±3.7 vs. 4.5±3, p=0.12). In cross-sectional analyses, individuals who quarantined had higher PSQI scores than non-quarantined individuals (6.1 ±3.9 vs 5.0±3.5, p<0.01). The quarantine status-dependent differences were significant for women (6.4±4 vs 5.2±3.7, p<0.01) and older adults (6.6±0.1 vs 5.5±3.3, p=0.04). Differences by quarantine status were attenuated after adjusting for age and gender. Conclusions: Subjective sleep quality declined during the COVID-19 pandemic, particularly among women, older adults, and those compliant to quarantine orders.