Variations of absolute gravity measured with the JILAG-4 absolute gravimeter at intervals ranging from 2 hours to 5 years are reviewed to ascertain short- and long-term instrument stability. We find that the standard deviation of the twenty-four 2-hourly drop set means taken during a given station occupation is 1--2 μGal when natural or man-induced microseismic condition are low and 3--5 μGal when the microseismic activity is high. The standard deviations of the station gravity values obtained by repeated occupations weeks or years apart are within these same ranges, with lower standard deviations found again at bedrock sites where the microseismic noise is low. Based on the repeatability of observations since the beginning of the measurements program in 1987, there is no indication for drift, gradual deterioration, or aging of the instrument. However, because of the degraded performation of the lasers used since 1990, the standard deviation of repeated station occupations increased from 2.27 to 2.87 μGal, and data had to be rejected at several sites. Individual station gravity values in excess of ¿3 μGal from the station mean are found mostly at those sites where density variations between reoccupations are expected on the basis of geological conditions, usually due to groundwater table fluctuations and/or soil moisture changes. ¿American Geophysical Union 1993