The objective of this study was to estimate the financial cost of developing new imaging agents for clinical use and to discuss the effects of these costs on the future clinical imaging agent environment. Publicly available financial data from the annual reports of major companies developing and selling imaging agents were examined and the data used to develop cost estimates. These estimates were compared with the in-depth data and analyses available for the development costs of therapeutic drugs. The cost of developing a drug for diagnostic imaging to commercialization is in the 100 dollars to 200 million dollars range, whereas a blockbuster imaging drug has current sales of 200 dollars to 400 million dollars. Most of these blockbuster imaging agents have been on the market for some time. The majority provide morphologic images with general indications in a slowly changing section of the market. Future agents will most likely address smaller markets and be in the rapidly developing molecular imaging field. The costs are high and are a significant brake on the development of imaging agents for commercialization. If new imaging agents are to realize their commercial potential, ways must be found to make the financials more attractive. The prices per dose are currently low so they must either be greatly increased for new imaging agents, with a corresponding increase in the value of the information they provide, or the use of imaging agents must be widened and/or their development made less costly in time and money. Without addressing these issues, the commercialization of new imaging agents will continue to be slow and may get slower. This will impact the progress of imaging agents toward use as validated biomarkers.