  We discuss the identification of sources detected by ISO at 6.7 and 15 micron
in the Hubble Deep Field (HDF) region. We conservatively associate ISO sources
with objects in existing optical and near-infrared HDF catalogues using the
likelihood ratio method, confirming these results (and, in one case, clarifying
them) with independent visual searches. We find fifteen ISO sources to be
reliably associated with bright [I(AB) < 23] galaxies in the HDF, and one with
an I(AB)=19.9 star, while a further eleven are associated with objects in the
Hubble Flanking Fields (ten galaxies and one star). Amongst optically bright
HDF galaxies, ISO tends to detect luminous, star-forming galaxies at fairly
high redshift and with disturbed morphologies, in preference to nearby
ellipticals.

Astrophysics