Hydrogen bonds of the type N-H··O which occur in interactions between N-methyl methyl carbamate or N-phenyl methylearbamate and (i) a second carbamate, (ii) an ester, and (iii) an ether are studied by ab initio methods using a minimal MINI-1 basis set. Of the three, the ether forms the strongest complex with a carbamate. Replacement of the methyl group bonded to the proton-donating N of the carbamate by a phenyl group leads to a somewhat stronger H-bond in all cases. The electron density patterns are typical of rearrangements that normally accompany H-bond formation.