Nurses are physically exhausted with an incidence of work-related musculoskeletal disorders (MSDs), especially those working in critical care units that require exhaustive physical efforts to fulfill patients' needs. The current study aims to assess work activities related to the occurrence of MSDs in nurses working in critical care units. A descriptive cross-sectional study was conducted on a sample of 100 nurses of critical care units, and the data were collected via a survey questionnaire. The study was conducted at King Fahad University Hospital for three months from February to April 2019. The study findings revealed that work activities related to MSD were associated with sociodemographic data, age, and neck pain (rho = 0.063) (=0.03) and lower back pain (rho = 0.89) (=0.03); education level with hip/thigh pain (rho = 0.64) (=0.03); standing time with shoulder pain (rho = 0.66) (=0.04), wrist/hand pain (rho = -0.75) (=0.05), hip/thigh pain (rho = -0.78) (=0.004), and knee pain (rho = -0.77) (=0.005). An increased prevalence of MSDs with lower back pain (92%) and upper back pain (56%) was estimated among the nurses, and a negative impact of work-related MSDs on occupational health and daily life activities of the nurses was also observed. The study concluded that the occurrence of MSDs is significantly associated with sociodemographic data: age, BMI experience level, and educational level of nurses of critical care units.