A sensor based on light-induced thermoelastic spectroscopy (LITES) with a fiber-coupled multipass cell was demonstrated for carbon monoxide (CO) detection. The fiber-coupled structure has the merits of reducing optical interference and difficulty in optical alignment and increasing system robustness. A 1.57 µm continuous wave distributed feedback diode laser was used as the excitation source. A minimum detection limit of 9 ppm was obtained, and the calculated normalized noise equivalent absorption coefficient was $1.15\times {10}^{-7}{\mathrm{cm}}^{-1}·\mathrm{W}·{\mathrm{Hz}}^{-1/2}$. The reported CO-LITES sensor showed excellent linear concentration response and system stability.