In order to improve our understanding of thromboemboli adhesion and removal in acute ischemic strokes, we seek to characterize the mechanical properties of embolus analogs and the effects of paraformaldehyde fixation. Both cyclic compression and stress-relaxation tests were performed to develop relationships to the behavior of thromboemboli in vivo. Order of magnitude differences were observed in the stress stress-strain curve slopes but similar behavior was seen in the normalized stress-relaxation data.