Supernovae play a key role in the dynamics, structure, and chemical
 evolution of galaxies.  The massive stars that end their lives as
 supernovae live for short enough times so that many are still associated
 with dusty star formation regions when they explode, making them difficult
 to observe at visible wavelengths.  In active star forming regions
 (galactic nuclei and starburst regions), visible extinction is especially
 severe.  Thus, determining the supernova rate in active star forming
 regions of galaxies, where the supernova rate can be one or two orders of
 magnitude higher than the average, has proven to be difficult.  From
 spectra we obtained of SN1987A, we know that supernovae have emission from
 a set of 4 strong lines in the mid-ir.  These lines include [NiII] 6.63
 um, [ArII] 6.98 um, Pf alpha 7.45 um, and [CoII] 10.52 um.  The
 relative strengths of the lines changes over time as the supernova shell
 expands.  The [NiII] emission line is a unique supernova signature, and
 in SN1987A it was the strongest line in the infrared for a period of a year
 and a half after the explosion.  Since dust extinction is much less in the
 mid-ir than at visible wavelengths (eg.  A(6.63)/A(V) = 0.025), the NiII
 line can be used as a sensitive probe to detect recent supernovae.  We
 propose to use ISOCAM with its CVF to observe a selection of infrared
 luminous nuclei of starburst galaxies to determine the supernova rate in
 galactic nuclei and starburst regions.  ISO is essential for these
 observations since the key supernova indicator, the 6.63 um [NiII] line
 is unobservable from ground-based telescopes, and the expected line
 intensities are too weak to be observed from existing airborne telescopes.