A comparison is made of the elastic response of fresh pericardial tissues at 25, 37, and 42°C, and also of fresh and glutaraldehyde-fixed tissues. Strips of bovine pericardial tissues cut perpendicular to the base-apex axis of the heart were used. An Instron machine was used for uniaxial tensile tests, and the strain-rate used was 666.7%•min^-1. No significant differences in tissue mechanical properties were observed for temperature values of 25, 37, and 42°C. However tissues fixed in a glutaraldehyde solution were more extensible than fresh tissues. The elastic responses of tissues preserved for 1 day in glutaraldehyde are not very different from those preserved for up to 10 days.