We present results of the first ground-satellite correlation study of ion cyclotron wave events inside geosynchronous orbit. We found several intervals during which waves at the same frequency were observed simultaneously by the DE I Goddard Space Flight Center Fluxgate Magnetometer and by the Air Force Geophysics Laboratory Magnetometer Network. This represents about 33% of the intervals during which waves were seen on the ground and DE I was in a favorable location (near the geomagnetic equator around L=4.6) to observe the wave generation region. Three of seven simultaneous events showed a positive correlation when a detailed correlation analysis was performed. The broadband nature of the other events prevented any detailed correlation analysis. Peaks in the cross-correlation function occurred at delays of 30--100 s and are interpreted as the group delay time of signals from space to the ground station. The small number of events seen in space during conjunction intervals results from the satellite's path missing the source region. When sources are missed by the satellite path, they either exist at higher or lower L shells and are ducted in the ionosphere to the network (L=3) or they exist at the satellite L shell but are missed due to their small spatial extent in local time. ¿1991 American Geophysical Union