Y-doped (1-x mol%)BaTiO3-x mol%(Bi1/2Na1/2)TiO3 (BBNTx) lead-free positive temperature coefficient of resistivity (PTCR) ceramics were prepared using a conventional solid sintering method. The Ba/Ti ratio was adjusted to obtain the optimized PTCR property. The results show that all 0.2 mol% Y-doped BBNT15 samples with various Ba/Ti ratios have formed a single tetragonal perovskite phase by sintering in an N-2 atmosphere. The sample with 5 mol% (Bi1/2Na1/2)TiO3 has only a minor PTCR effect (maximum resistivity [rho(max)]/minimum resistivity [rho(min)]) when sintered in N-2. However, the PTCR effect is enhanced over 3.0 orders of magnitude when the (Bi1/2Na1/2)TiO3 content is >8 mol%. The PTCR characteristics of the samples with Ti excess are superior to those with Ba excess. The optimum composition of 0.2 mol% Y-doped BBNT15 with Ba/Ti = 0.99, sintered at 1250 degrees C for 3 h in an N-2 atmosphere, has a low room-temperature resistivity (rho(25)) of similar to 100 Omega.cm and a high PTCR effect of similar to 4.8 orders of magnitude with T-c around 190 degrees C.