High-copper amalgam alloys containing 5% and 10% admixed indium, shown in previous studies to have improved properties and acceptable biological behavior, were evaluated in a clinical study designed to examine factors relating to clinical success. One hundred and seventy-five Class I and Class II amalgam restorations were placed in 25 patients. Each patient received all three dispersed-phase amalgams tested: without indium (Dispersalloy), with 5% indium (Indisperse 5), with 10% indium (Indisperse 10). After 30 months, 22 patients were recalled and 146 restorations evaluated. The margins of the indium-containing amalgam restorations incurred slightly less marginal breakdown, an effect that could be attributed to the addition of admixed indium and to the increase in silver-copper eutectic spheres which is found in these alloys. These amalgams also demonstrated a slightly darker appearance, and were slightly rougher than the non-indium-containing amalgam. These differences were minor; at 30 months, all restorations were well within the clinically acceptable range for each parameter evaluated.