The authors present an evaluation of published antimony concentrations in human blood. It is the last installment of a series of studies on the use different biological tissues in human biomonitoring that have appeared in Critical Reviews in Environmental Science and Technology. The objective was to assemble and evaluate published data from a methodological point of view and establish, if possible, a range of plausible values for antimony concentrations in whole blood and plasma and/or serum for nonexposed humans. Determining the concentration of antimony in blood is far from straightforward because samples are highly prone to contamination and values are low, close to the detection limits of the techniques available. In combination with the lack of adequate certified reference materials, this makes it impossible to establish a value for antimony content in the blood of healthy, non-exposed individuals based on published values. However, more recent results have opened up the possibility of suggesting a concentration ceiling of around 1 μg L–1. The review includes a detailed discussion of the main problems encountered in determining antimony in this complex matrix that may prove useful as a guide for future work.