The fault plane and overall coseismic slip of the 1989 Loma Prieta, California, earthquake (MS=7.1) are well determined [Plafker and Galloway, 1989>. Teleseismic waves can be used to determine the time history of moment release. We invert a data set of ten broadband P and SH waves for the most general point source description: the five moment tensor rate functions. The linear inversion also provides formal estimates of model uncertainty. While the moment tensor rate functions suggest a different focal mechanism for the first few seconds of the rupture process, it is not statistically significant at the 95% level. We can thus proceed to invert for one single time function (the source time function), and five scalars (the moment tensor). The major double couple that we find (strike 138¿¿6¿ clockwise from North, dip 76¿¿5¿, slip angle 120¿¿10¿) agrees with the results of Plafker and Galloway [1989>. The minor double couple is small (1%). The best point source depth is about 10 km. Several broadband P waves show that a small precursor occurred a few seconds before the main pulse of moment release. The duration of the source time function is 9 s, with a moment of 2¿0.5¿1019 Nm. A bilateral rupture with velocity of 2.8 km/s and 9 s duration encompasses the aftershock region. ¿ American Geophysical Union 1990