  The possibility of positronium detection at radio wavelengths is investigated
in detail. For orthopositronium, the fine structure lines of the n = 2 level
(1.62 cm, 2.30 cm and 3.48 cm) may be probably detected by radiotelescopes of
next generations with the sensitivity around 1 microJansky. The spin-flip line
of the ground state (0.147 cm) may be observed from sources with a narrow
annihilation line by modern telescopes with the sensitivity around 10
microJansky. In the fine structure and spin-flip lines a maser effect is
produced. The expected radio fluxes in the spin-flip line can reach detected
limits for certain source geometries and optimal physical conditions inside the
source.
