The purpose of this prospective multi-site study was to determine the frequency of intravenous (IV) site symptoms and to develop a preliminary model of the factors implicated in the number of these symptoms. In a sample of 514 patients from four institutions, IV site symptoms including pain, redness, swelling, induration, and/or a venous cord were present in 205 (39.9%) of the patients. The IV catheters were in place an average of 48.7 hr. There were no significant differences in symptoms by hospital site. Using multiple regression techniques, a seven-factor model explained 18% of the variance in number of IV site symptoms. Further research is required to explore other potential causes for the numbers of IV site symptoms.