We present the first simultaneous observations of chorus activity and energetic particles from near-geosynchronous orbit by using data from the Aerospace Corporation VLF receiver and the UCSD charged particle detector on the SCATHA satellite. We find that, for the 5 days studied, June 23--27, 1979, every encounter with injected clouds of energetic electrons was accompanied by chorus activity. We conclude that dawnside chorus is generated by substorm-injected, anisotropic clouds of electrons with energies between 10 and 100 keV.