Nitrous oxide (N2O) is used in medical and veterinary procedures and in other sectors. Personnel exposure to this compound can have serious health effects. The current method used to sample N2O is based on diffusive sampling on a 5 angstrom molecular sieve, but this is not ideal because a back-diffusion phenomenon is observed. In this study, cationic ZSMS zeolites were tested as possible alternative sampling supports. Zeolites were prepared, characterized, and tested for nitrous oxide adsorption. The influence of water vapor in the stream was also investigated. The performances of the various adsorbents tested were found to depend on the number and the nature of the exchange cations. The uptake rate of each zeolitic adsorbent was then determined to investigate whether back-diffusion occurred. The highest adsorption capacities, in the presence or absence of water vapor, were obtained with Ba-exchanged ZSM5 zeolites with an Si/Al ratio of 11; no back diffusion was observed on this adsorbent. BaZSM5(11) thus appears to be a suitable solid to replace 5 A molecular sieve for diffusive N2O sampling.