Scanning tunneling microscopic studies of silver catalysts dispersed on highly oriented pyrolitic graphite (HOPG) with 2, 5 and 10 wt% metal loading prepared by wet impregnation and hydrogen reduction show spherical crystallites, with the 2 wt% catalysts having an average crystallite size of approximately 2 nm and the 5 and 10 wt% catalysts with size distributions of 2-5 and 4-12 nm respectively. The Ag catalysts prepared by NaBH4 reduction show a narrower size distribution. Pt/HOPG catalysts with 2 and 5 wt% metal loading prepared by wet-impregnation and hydrogen reduction show large (2-11 nm) raft-like crystallites; small crystallites (approximately 1 nm) could be obtained by NaBH4 reduction. Tunneling spectroscopic measurements reveal the non-metallic nature of crystallites on the surface of Ag(2 wt%)/HOPG as well as Pt/HOPG prepared by NaBH4 reduction.