We have obtained a deep i-band image of the blazar 3C 279 while the target was in a low optical state .
Due to the faintness of the optical nucleus we have made the first detection of the host galaxy .
The host galaxy has an apparent I-band magnitude of 18.4 \pm 0.3 and an effective radius of ( 2.7 \pm 1.1 ) arcsec .
The luminosity of the host galaxy M _ { R } = -23.8 is consistent with the luminosities of other radio-loud quasar host galaxies .
Using the empirical correlation between bulge luminosity and central black hole mass M _ { bh } we estimate \log ( M _ { bh } / M _ { \odot } ) = 8.9 \pm 0.5 , broadly consistent with values obtained by photoionization methods .