The acetaldehyde molecule is ubiquitous in the interstellar medium of our galaxy, and due to its dense and complex spectrum, large dipole moment, and several low-lying torsional states, acetaldehyde is considered to be a "weed" molecule for radio astronomy observations. Mono-^13^C acetaldehydes ^13^CH_3_CHO and CH_3_^13^CHO are likely to be identified in astronomical surveys, such as those available with the very sensitive ALMA telescope. Laboratory measurements and analysis of the millimeter and submillimeter-wave spectra are the prerequisites for the successful radioastronomical search for the new interstellar molecular species, as well as for new isotopologs of already detected interstellar molecules. In this context, to provide reliable predictions of ^13^CH_3_CHO and CH_3_^13^CHO spectra in millimeter and submillimeter wave ranges, we study rotational spectra of these species in the frequency range from 50 to 945GHz. The spectra of mono-^13^C acetaldehydes were recorded using the spectrometer based on Schottky-diode frequency-multiplication chains in the Lille laboratory. The rotational spectra of ^13^CH_3_CHO and CH_3_^13^CHO molecules were analyzed using the Rho axis method.