Abstract The effect of nano-sized PbO (10–30nm) addition on the transport critical current density, Jc of (Bi1.6Pb0.4)Sr2Ca2Cu3O10 (PbO)x (x=0–0.15wt%) was investigated. Jc of PbO added pellet samples showed the maximal value at x=0.05wt%. Using this result, Ag-sheathed (Bi1.6Pb0.4)Sr2Ca2Cu3O10 (PbO)x/Ag tapes (x=0 and 0.05wt %) were fabricated by the powder-in-tube (PIT) method. The tapes were sintered for 50h and 100h at 845°C. The temperature dependence of Jc for the non-added and PbO added tapes in applied field was investigated. Jc of the non-added tapes was 4510A/cm2 at 40K and 949A/cm2 at 77K. Jc of (Bi1.6Pb0.4)Sr2Ca2Cu3O10 (PbO)0.05/Ag tape sintered for 100h was 26,800A/cm2 at 40K and 10,700A/cm2 at 40K, which was higher than the tapes sintered for 50h (8590A/cm2 at 40K and 1880A/cm2 at 77K). Nano-sized PbO added tapes sintered for 100h showed a higher Jc (more than 10 times) under magnetic field (0–0.75T) compared with the non-added tape. A combined effect of enhanced flux pinning and improved microstructure led to the significant increase in Jc of the nano-sized PbO added tapes.