The ν1 band of OCS has been measured in the wavenumber range 2026 to 2081 cm-1 to an accuracy better than 0.0008 cm-1 using a diode laser spectrometer. The width of the observed lines is essentially Doppler-limited. The observed lines could be assigned to the following hot bands: 1110-011O, 1200-0200, 1220-0220, 1001-0001, 1111-O111 of OCS and to 1000-0000 and 1110-0110 of the isotopic species OC34S and OC33S in natural abundances. These data provide a secondary standard in this wavelength region.