Reliable and sustained venous access is imperative for the successful treatment of patients with malignant disease. Its institution is achieved by the proactive assessment of patients’ venous access needs. Assessment tools may facilitate this process. This article presents a review of the literature on the three factors fundamental to assessment of patients’ venous access needs: patient characteristics, treatment characteristics and available devices. This literature review contributed to the development of two venous access assessment tools that can be used by nurses: the adult Venous Assessment Tool (VAT) and the algorithm Deciding on IntraVenous Access (DIVA). They are presented in part two of this article, which will be published next week.