Workload perception is of interest to researchers and policymakers as it captures subjective assessments of nurses' workload which has implications for staffing and patient outcomes. We aimed to describe repeated assessments of nurses' perceived workload among registered nurses (RNs) in day and night shifts and to examine the association of perceived workload with workdays, units, and nurse-staffing. Repeated data on the indictors of interest were collected from 90 RNs across 91 shifts in a Lebanese acute-care hospital. Perceived workload was assessed using the NASA-Task-Load Index (NASA-TLX). Linear mixed-effect models were used for analysis. Mean perceived workload was high reaching 6.63 (95% confidence interval [CI] = 6.34, 6.92) in day and 5.90 (95% CI = 5.43, 6.36) in night shifts. In mixed-effect models, perceived workload was lower on weekends/holidays as compared to weekdays in day (ß = -.32; 95% CI = -0.53, -0.12) and night (ß = -.46; 95% CI = -0.85, -0.07) shifts. Higher perceived workload (ß = .19; 95% CI = 0.04, 0.33) was associated with higher patient-to-nurse ratio in the day but not night shifts. Repeated workload assessments support the presence of elevated perceived workload among RNs which is related to weekdays and higher patient-to-nurse ratio. Future investigations would benefit from better characterization of workload particularities to address perceived burden and improve organizational and management decisions.