In clinical practice, nurses perform different activities that exceed direct care of patients, and influence workload and time administration among different tasks. When implementing changes in an electronic nursing record, it is important to measure how it affects the time committed to documentation. The objective of this study was to determine the time dedicated to different activities, including those related to electronic documentation prior to implementing a redesigned nurse chart in an Electronic Health Record at the Hospital Italiano de Buenos Aires. An observational work sampling study was performed. Nursing activities observed were categorized as direct care, indirect care, support, non-patient related, and personal activities. During the study, 74 nurses were observed and 2,418 observations were made in the Intensive Care Unit (32.22%), the Intermediate Care Unit (29.57%), and the General Care Unit (38.21%). Nurses' activities included 37.40% of direct care, 41.18% of indirect care, 0.43% support tasks, 11.14% non-related to patient tasks, and 9.77% personal activities. The results allow for the estimation of the impact of a nursing e-chart on nurses' activities, workflow and patient care.