This article discusses the relationship between sci-tech libraries and serials agents, noting that the handling of sci-tech journals is a particularly lucrative market for the serials agent, owing both to the high cost and to the relative tractability of sci-tech journals. The two principal pricing algorithms of serials agents are described and their effects (which, for sci-tech libraries, differ substantially from each other) are analyzed. Results of a survey concerning the relationship between sci-tech libraries and their serials agents are reported. The conclusions drawn are that sci-tech libraries have substantial leverage in their dealings with serials agents, but that they have not made adequate use of the leverage, and further, that sci-tech libraries are in general being charged fees that are higher than necessary-higher than could reasonably be bargained for if sci-tech libraries were to exercise their leverage more aggressively. There is therefore an opportunity cost involved inc arefully reviewing one's serials agent relationships; there may well be resources being spent that could be better deployed elsewhere.