The structure of N,N-dimethylhydroxylamine 1 has been studied in the gas phase by electron diffraction, in the solid state by low-temperature X-ray crystallography and by ab initio methods. The analysis of the gas-phase data was carried out by the recently established method of applying flexible restraints (based on the results of ab initio calculations) to otherwise unrefinable parameters and shows the advantage of this method in comparison with conventional gas-phase structure analysis. The structural parameters of the free molecule (gas phase) are compared with those of the chain aggregates, which 1 forms in the crystal by N ⋯ H–O hydrogen bonding [the intermolecular NO distance is 2.777(4)Å]. The core of 1 has been found to be affected little by the formation of hydrogen bonds. Important structural parameter values were found to be [gas phase (r_α, <_α), crystal structure (values for one of the two independent molecules)]: r(NO) 1.448(11), 1.452(2)Å; r(NC) 1.463(7), 1.446(4) and 1.448(4)Å; < (CNO) 106.4(4), 106.5(2) and 104.8(2)°; <(CNC) 110.4(15), 110.5(2)°.