  Since its launch in October 2002, ESA's INTEGRAL observatory has enabled
significant advances to be made in the study of Galactic nucleosynthesis. In
particular, the imaging Ge spectrometer SPI combines for the first time the
diagnostic powers of high resolution gamma-ray line spectroscopy and moderate
spatial resolution. This review summarizes the major nucleosynthesis results
obtained with INTEGRAL so far. Positron annihilation in our Galaxy is being
studied in unprecented detail. SPI observations yield the first sky maps in
both the 511 keV annihilation line and the positronium continuum emission, and
the most accurate spectrum at 511 keV to date, thereby imposing new constraints
on the source(s) of Galactic positrons which still remain(s) unidentified. For
the first time, the imprint of Galactic rotation on the centroid and shape of
the 1809 keV gamma-ray line due to the decay of 26Al has been seen, confirming
the Galactic origin of this emission. SPI also provided the most accurate
determination of the gamma-ray line flux due to the decay of 60Fe. The combined
results for 26Al and 60Fe have important implications for nucleosynthesis in
massive stars, in particular Wolf-Rayet stars. Both IBIS and SPI are searching
the Galactic plane for young supernova remnants emitting the gamma-ray lines
associated with radioactive 44Ti. None have been found so far, which raises
important questions concerning the production of 44Ti in supernovae, the
Galactic supernova rate, and the Galaxy's chemical evolution.
