Water imbibition and effects of hot water (65C) on germination were evaluated on seed from 20 cotton strains produced in 1984 and 1985 and on seed from the 1985 and 1986 cotton variety tests in Mississippi. Water imbibed in one hour by untreated seed was determined on a wet weight basis. Seed, treated for 0, 30 (or 35), and 40 (or 45) minutes, were germinated for 7 days at 20C. Within each test, significant variation was found for imbibition rate and germination of hot water treated seed. Similar response of genetically related strains suggested that tolerance to hot water treatment is an inherited characteristic. Variation among varieties within varietal groups was found. Relative imbibition rates and effects of treatments on the genotypes were consistent between years. With few exceptions, genotypes which imbibed water slowly had high tolerance to hot water stress.