The complex potential energy surface for the reaction of singlet methylene((CH2)-C-1) with nitrous oxide (N2O) has been investigated in detail using B3LYP/6-31G(d,p) and single-point QCISD(T)/6-311G(d,p) methods. The association of (CH2)-C-1 with N2O was found to be a barrierless process forming an energy-rich adduct CH2-NNO (al). Our calculations show that the products P-1(N-2+H2CO) and P-13(NO+HCN+H) are the major products for the title reaction. The other products, including CO and H-2, are minor products. The product Pi(N2+H2CO) can be obtained through R -->a(1)-->a(2)-->b --> P-1(N-2+H2CO) (rl), whereas the product P-13(NO+HCN+H) can be obtained through two competitive channels R -->a(1)-->P-4(HNO+HCN)-->P-13(NO+HCN+H) (r8) and R -->a(1)-->a(2)-->P-5(NO+H2CN)-->P-13(NO+HCN+H) (r12). At high temperatures, the;direct abstraction channel leading to product N-2+H2CO may become feasible. Our work can assist experiments to identify the products of the (CH2)-C-1+N2O reaction.