This study has measured the density-normalized effective ionization coefficients (α-η)/N, the electron drift velocity V e and the diffusion coefficient D L in nitrous oxide (N_2O) using a pulsed Townsend technique. The range of the overall density-normalized electric field strength E/N is from 100 Td to 400 Td (1 Td=10 17 V·cm2). From the above plots of (α-η)/N, we have derived the limiting field strength, (E/N) lim ≈ 150 Td, which is the value of E/N at which (α-η)/N=0. This study has measured the density-normalized effective ionization coefficients (α-η) / N, the electron drift velocity V e and the diffusion coefficient DL in nitrous oxide (N_2O) using a pulsed Townsend technique. The range of the overall density-normalized Electric field strength E / N is from 100 Td to 400 Td (1 Td = 10 17 V · cm 2) From the above plots of (α-η) / N, we have derived the limiting field strength, (E / N) lim ≈ 150 Td, which is the value of E / N at which (α-η) / N = 0.