  We present new optical and {\it Chandra} observations of the field containing
the ultraluminous X-ray source NGC1313 X-2. On an ESO 3.6 m image, the {\it
Chandra} error box embraces a $R=21.6$ mag stellar-like object and excludes a
previously proposed optical counterpart. The resulting X-ray/optical flux ratio
of NGC 1313 X-2 is $\sim 500$. The value of $f_X/f_{opt}$, the X-ray
variability history and spectral distribution indicate a luminous X-ray binary
in NGC 1313 as a likely explanation for NGC 1313 X-2. The inferred optical
luminosity ($L\approx 10^5 L_\odot$) is consistent with that of a $\approx 10
M_\odot$ companion.
