Colloidal particles of environmental concern often have non-spherical shapes (e.g. bacteria). However, theories/models such as the classical filtration theory have been developed based on behavior of spherical particles. The objective of the present study is to examine the effect of particle shape on the retention (e.g., attachment and straining) and release of colloids in saturated porous media. Colloid transport experiments were conducted in water-saturated glass bead columns using colloids dispersed in DI water and an electrolyte solution (IS=200 mM, pH=10) with two- and three-step methods to measure colloid retention and release. The particles employed in the experiments were carboxylate-modified latex colloids of spherical (500 nm) and rod shape (with an aspect ratios of 7.8). The rod-shaped particles were stretched from the spherical particles so that they have the same volume. Glass beads, which are of 0.22 mm in diameter and negatively charged, were acid-treated prior to use. Columns were dissected to obtain the retained colloid spatial distribution profiles at the end of both two- and three-step experiments. Measurements and analysis of the colloid breakthrough curves indicate that retention of the spherical particles occurred mainly in second minimum energy well in both DI water and the 200 mM electrolyte solution, but more significant at the high ionic strength. Experimental data suggest that straining is also an important mechanism of particle retention. Elution with DI water allowed distinction between secondary energy minimum retention, where all retained particles re-entrained upon introduction of DI water, from straining. Results from the on-going experiments with the rod-shaped particles will be compared with the behavior of spherical particles. Theoretical and modeling analysis will be provided to explain the effect of particle shape on colloid retention, especially on the straining process.