Neutral clusters of nitrous oxide, (N2O)m, formed in a supersonic nozzle expansion were ionized by impact of high-Rydberg krypton atoms, Kr**, and slow electrons having kinetic energies of 1-10 eV. Negative cluster ions, (N2O)nO- (n ≥ 3) and (N2O)n- (n ≥ 5), were produced by Kr** impact, while (N2O)nO- (n ≥ 0) and trace amounts of (N2O)nNO- (n ≥ 0) and (N2O)n- (n ≥ 1) were observed by electron impact. The intensity ratio, (N2O)n-/(N2O)nO -, produced by Kr** impact was 2 orders of magnitude larger than that by electron impact. These observations are interpreted as follows: The (N2O)nO- ions observed in both cases are produced via the N2O-(2Σ+)(N2O) m-1 resonance state, where the N2O-(2Σ+) unit is solvated by the rest of the molecules. In the Kr** impact ionization, several N2O molecules are evaporated after dissociation of N2O-(2Σ+)(N2O) m-1 into (N2O)m-1O- + N2. Formation of (N2O)n- by Kr** impact proceeds via the N2O-(2Π)(N2O)m-1 resonance state followed by substantial evaporation of N2O. In contrast, intracluster ion-molecule reactions in (N2O)m-1O- originating from N2O-(2Σ+)(N2O) m-1 give rise to (N2O)nNO- and (N2O)n- observed by EI.