Annual bluegrass (Poa annua) ecotypes collected from golf course putting greens were evaluated for resistance to pink snow mould (Microdochium nivale) under natural and controlled conditions. Field plots consisted of thirty ecotypes transplanted into existing creeping bentgrass (Agrostis stolonifera) putting greens in the fall, which allowed the turf to cold acclimate. Inoculation occurred in early winter. Weekly visual evaluation conducted immediately after snowmelt over six weeks revealed significant differences in the ability of the ecotypes to resist pink snow mould attack and to recover after snowmelt. Cold chamber plots consisted of the same ecotypes used in the field study plus two bentgrasses transplanted into tubes. The ecotypes were acclimated in a cold chamber before they were inoculated with infested wheat bran. Visual evaluation during the incubation period revealed significant differences in the ability of the ecotypes and the bentgrasses to resist pink snow mould attack.