Metal-containing nanorods are of great interest from a number of technological perspectives, and they are also present in the natural environment. Here we show that dissolution, both rate and extent, is greater for rod-shaped alpha-FeOOH particles on the nanoscale at pH 2 relative to microrods. However, when nanorods aggregate, either at lower pH and/or high ionic strength, dissolution is either completely quenched or severely quenched, by orders of magnitude. Furthermore, nanorod suspensions are less stable compared to microrod suspensions, resulting in nanorod aggregation under conditions where microrods stay fairly well dispersed. Although recent evidence suggests that particle size is a controlling factor in the solubility of iron oxides, a fundamental understanding of the influence of particle size is just beginning to emerge. The results presented here not only address some of the complexities of size-dependent dissolution of metal-containing nanorods in solution, they also contribute to our understanding of the factors that can influence Fe-mobilization in the global environment.