Technical Abstract: The resistance of 53 highbush blueberry (Vaccinium corymbosum L.) cultivars and selections to the blight phase of mummy berry disease (Monilinia vaccini corymbosi (Reade) Honey) was evaluted under controlled conditions. Blight levels observed in the 1993 test ranged from 1 to 78% and significant differences among cultivars were noted. In 1994, infection levels were lower and ranged from 0 to 43%, with significant differences again occurring. Several cultivars exhibited mummy berry blight resistance in both years. Ranking most resistant to less resistant were 'Jersey', 'Elliott', 'Bluejay', 'Duke', 'Stanley', 'Darrow', 'Meader', and 'Angola'. Among the cultivars observed as being consistently blight susceptible were 'Bluehaven', 'Bluegold', 'Northblue', 'Croatan', 'Northsky', 'Sierra', 'Harrison', and 'Murphy'. The consistent resistant reaction of certain cultivars indicates they would be the better r choice as parents for introducing resistance into a breeding program. Th evaluation methodology developed in these tests will also be very useful in screening germplasm for new sources of resistance and progeny from a mummy berry resistance breeding program.