Development of the European red mite, Panonychus ulmi (Koch), in Nova Scotia was studied at three constant temperatures to construct a life table and establish the intrinsic rate of development. The threshold temperature for development was 10.6°C. The duration from the beginning of the egg stage to adult for females was 31.2, 20.5, and 14.0 days and for males 21.9, 19.6, and 12.8 days at 15°, 18°, and 21°C, respectively. The duration in degree-days above 10.6°C for females was 137.3, 151.7, and 145.2 and for males 128.0, 144.9, and 133.1 at the same three temperatures. The duration of the preoviposition period decreased, duration of the oviposition period remained constant, and the number of eggs laid increased with temperature. Life tables were constructed at 15°, 18°, and 21°C; the intrinsic rates of increase were 0.56,.092, and.134; net reproduction rates 10.06, 13.50, and 17.37; and mean generation times were 41.4, 28.3, and 21.3 days, respectively.