A two-part project was undertaken to develop a reliable, valid, and easily administered instrument for measuring parental participation in the care of the hospitalized child. Part I of this project was concerned with identifying parental participation activities. Particular attention was given to establishing the content validity of the activities. Three sources were used to identify the activities: parents of hospitalized children, previous research, and an expert panel,Eleven parental involvement activities were identified through interviews with 24 parents of hospitalized children and through daily diaries of parental activities kept by these same parents. Verification of these activities took place through a review of previous research and submission to a panel of 19 experts.All activities identified through the parents were further validated through previous research and an expert panel. The eleven activities can be categorized according to level of involvement and also according to focus.