Objectives To assess whether there is a difference between the net prices of medical products used by Dutch hospitals and, if there is, how this difference can be explained. Design Cross-sectional self-administered electronic survey. Setting We surveyed the prices paid for 17 commonly used medical products, such as pacemakers, gloves and stents in 38 Dutch hospitals (including general, specialised and academic hospitals) in 2017. Hospitals voluntarily and anonymously provided these data and received a personalised free benchmark tool in return. This tool provides information about the variance in prices of the medical products they buy. Participants 38 out of 79 hospitals entered and completed the study. Primary and secondary outcome measures Actual price paid excluding Value Added Tax (VAT) per item, the order size per year, total spending for an assortment group and total spending for all products purchased from a specific supplier were measured. Results We found large price variations for the medical products surveyed (average coefficient of variation of 71%). In general, these differences were hard to explain (average R2 of 26%). Only purchasing volume (for 8 out of 17 products) was significantly associated with the net price paid by a hospital. Total spending for an assortment group (in euros with a specific supplier) and total spending (for all products in euros with a specific supplier) were not related to the net price paid. Conclusions We conclude that only purchasing volume is associated with lower prices paid. Total spending for an assortment group and total spending for all products purchased from a specific supplier are not. These results are in stark contrast to expectations based on economic theory. Other sources of differences in bargaining power might explain these findings. Further research might involve comparing prices across countries.