Absorption spectra of carbon oxide, confined in nanoporous silica aerogel, have been measured within 4100-4400 cm(-1) region at room temperature and at several pressures using Bruker IFS-125 HR Fourier spectrometer. Dependence of the half-width (HWHM) values on rotational quantum numbers is studied and compared with the data available in literature. It is found that variations in the half-width values for the confined CO at small quantum numbers are larger than at moderate ones. The influence of confinement tightness on rotational dependence is discussed. (C) 2015 Elsevier B.V. All rights reserved.