Technical Abstract: Fifty-one highbush blueberry (Vaccinium corymbosum L.) cultivars and selections were evaluated over three years for resistance to the fruit infection phase of mummy berry disease [Monilinia vaccinii-corymbosi(Reade)Honey]. A second group of 17 cultivars was evaluated for 2 years. Fruit infection incidence in 1995 ranged from 6 to 61%, in 1996 from 0 to 37% and in 1997 from 0.4 to 70% in the 51 cultivar group. In the 17 cultivar group fruit infection incidence ranged from 0 to 45% in 1996 and from 2.8 to 51.6% in 1997. There were significant differences among entries in all five tests. Several cultivars exhibited consistent mummy berry fruit infection resistance across all years of testing. Ranking most resistant to less resistant were 'Northsky', 'Reka', 'Northblue', 'Cape Fear', 'Puru', 'Bluejay' and 'Weymouth'. Among the cultivars consistently susceptible to fruit infection were 'Atlantic', 'Berkeley', 'Herbert' and 'E-176'. The consistent resistant reaction of certain cultivars indicates that they may be suitable as parents for introducing resistance into a breeding program. The evaluation methodology developed in these tests should be useful in screening germplasm for new sources of resistance and evaluating segregating progeny from crosses.