  Here we report the discovery of very high energy gamma-ray emission from the
radio emitting X-ray binary LS I +61 303 with the Major Atmospheric Gamma
Imaging Cherenkov (MAGIC) telescope. This high energy emission has been found
to be variable, detected 4 days after the periastron passage and lasting for
several days. The data have been taken along different orbital cycles, and the
fact that the detections occur at similar orbital phases, suggests that the
emission is periodic. Two different scenarios have been involved to explain
this high energy emission: the microquasar scenario where the gamma-rays are
produced in a radio-emitting jet; or the pulsar binary scenario, where they are
produced in the shock which is generated by the interaction of a pulsar wind
and the wind of the massive companion.
