We describe vertical cavity surface emitting laser (VCSEL) reliability tests comprising hundreds of parts and more than a million device hours. The VCSELs studied were of a previously described production design intended for local-area network data communication at 850 nm. Devices were operated at temperatures of 35, 80, 100, 125, and 150 degrees C and at currents of 5, 10, 15, 20, and 30 mA, and their operating characteristics were measured at room temperature. Additional groups were operated at 225 degrees C. Nominal operation is expected to be at 40 degrees C ambient and near 10mA; stresses due to temperatures and currents above the operating range accelerated degradation. The results support an Arrhenius- type failure-acceleration model with lognormal reliability distribution and lead to an 0.88-1.2- eV estimate for the failure activation energy. When tested at room temperature, typical VCSELs exhibited initial increases in power followed by decreases. The results were essentially independent of the package type (hermetic, unsealed, or overmolded plastic). Time- lapse video of degrading devices was employed in an effort to define the failure mode, which does not appear to be mediated by dark-line defects. Under normal operating conditions the observed VCSEL reliability is equal to, or better than, typical reliability results for other AlGaAs data communications lasers or LEDs.