Theory building in nursing and midwifery both to explain and inform practice is important to advance these professions via provision of a theoretical foundation. This research explored the process of perinatal data entry undertaken by midwives to explore the impact of the movement from paper to computer collection of data. Use of grounded theory methodology enabled theory building, leading to a theoretical understanding of the phenomenon and development of the Theory of Beneficial Engagement grounded in the data. Methods involved in-depth semistructured interviews with 15 users of perinatal data systems. Participants were recruited from 12 different healthcare locations and were utilizing three different electronic systems for data entry. The research question that guided the study focused on examining the influences of using the computer for perinatal data entry. Findings indicated that qualities particular to some midwives denoted engagement with perinatal data entry, suggesting a strong desire to enter complete, timely, and accurate data. The Theory of Beneficial Engagement provides a model of user engagement with systems for perinatal data entry consistent with other theories of engagement. The theory developed describes this phenomenon in a simple, elegant manner that can be applied to other areas where mandatory data entry is undertaken.