860 rotational ines of the almost unperturbedv∓14+v∓16component of thev4+v6band of CH379Br have been assigned in spite of overlaps with several other bands. Only a few sub-bands (KΔK= 1, -7, -8, -9) are subject to slight resonances. An RMS deviation of 0·0039 cm-1has been achieved by a leastsquares fit of 742 lines. As expected, theA′,B′,D′J,D′JKandD′Kmolecular conparison between the centres of both components of thev4+v6band allowed us to measure two anharmonicity constants:x46= -5·25 cm-1andg46= 0·89 cm-1.