Context : Low-frequency radio arrays are opening a new window for the study of the sky , both to study new phenomena and to better characterize known source classes .
Being flat-spectrum sources , blazars are so far poorly studied at low radio frequencies .

Aims : We characterize the spectral properties of the blazar population at low radio frequency compare the radio and high-energy properties of the gamma-ray blazar population , and search for radio counterparts of unidentified gamma-ray sources .

Methods : We cross-correlated the 6,100 deg ^ { 2 } Murchison Widefield Array Commissioning Survey catalogue with the Roma blazar catalogue , the third catalogue of active galactic nuclei detected by Fermi -LAT , and the unidentified members of the entire third catalogue of gamma-ray sources detected by Fermi -LAT .
When available , we also added high-frequency radio data from the Australia Telescope 20 GHz catalogue .

Results : We find low-frequency counterparts for 186 out of 517 ( 36 % ) blazars , 79 out of 174 ( 45 % ) gamma-ray blazars , and 8 out of 73 ( 11 % ) gamma-ray blazar candidates .
The mean low-frequency ( 120–180 MHz ) blazar spectral index is \langle \alpha _ { \mathrm { low } } \rangle = 0.57 \pm 0.02 : blazar spectra are flatter than the rest of the population of low-frequency sources , but are steeper than at \sim GHz frequencies .
Low-frequency radio flux density and gamma-ray energy flux display a mildly significant and broadly scattered correlation .
Ten unidentified gamma-ray sources have a ( probably fortuitous ) positional match with low radio frequency sources .

Conclusions : Low-frequency radio astronomy provides important information about sources with a flat radio spectrum and high energy .
However , the relatively low sensitivity of the present surveys still misses a significant fraction of these objects .
Upcoming deeper surveys , such as the GaLactic and Extragalactic All-Sky MWA ( GLEAM ) survey , will provide further insight into this population .