  The high mass X-ray binary LS I +61 303 has been observed over several months
in 2006 and 2007 with the VERITAS array of imaging air-Cherenkov telescopes. A
signal of high energy gamma rays with energies above 350 GeV is detected in
several orbital cycles of the binary system. The detected flux of gamma rays is
strongly variable with the orbital period of 26.5 days, while the maximum flux
(corresponding to about 10% of the flux of the Crab Nebula)is always found at
approximately apastron, suggesting a strong dependence of particle acceleration
and/or propagation on the relative position of the two objects in the system.
