The Advanced Camera for Surveys on board the Hubble Space Telescope has been used to obtain deep, high-resolution images of the giant elliptical galaxy NGC 3610, a well-established remnant of a dissipative galaxy merger. These observations supersede previous, shallower observations that revealed the presence of a population of metal-rich globular clusters of intermediate age (~1.5-4Gyr). We detect a total of 580 cluster candidates, 46% more than from the previous WFPC2 images. The new photometry strengthens the significance of the previously found bimodality of the color distribution of clusters.