Abstract: When the atomic oxygen density in the mesosphere and lower thermosphere region is derived by means of photochemical model calculations from OH nightglow emissions, a retrieval uncertainty, i.e. uncertainty of the density values obtained this way arises from the uncertainties of the input parameters. The retrieval uncertainty due to the uncertainties of atmospheric parameters and OH(8-3) band volume emission rate, the retrieval uncertainty due to the uncertainties of rate coefficients, and the retrieval uncertainty due to the uncertainties of all input parameters are analyzed using as an example the sudden death quenching model for OH airglow. The parameters the uncertainties of which have the largest contributions to retrieval uncertainty are found. The results show that all three retrieval uncertainties increase with altitude. The retrieval uncertainties caused by the uncertainties of the temperature and emission rate yield the largest contributions to the first retrieval uncertainty. The retrieval uncertainties caused by the uncertainties of the coefficients b(8) and A(8-3) yield the largest contributions to the second retrieval uncertainty.