The purpose of the study was to compare the mechanical properties of small femoral arteries from spontaneously hypertensive rats (SHR) and normotensive control Wistar-Kyoto rats (WKY) to determine whether these could contribute to the narrowed lumens and thicker medial layers observed during the development of hypertension. Rats were used at either 5, 12, or 24 weeks of age. Third order branches of the right femoral artery were mounted in a myograph for morphological measurement and determination of wall mechanical properties. At 5 weeks SHR and WKY arteries were structurally similar but progressive medial thickening and hypertrophy in conjunction with lumenal narrowing was observed in SHR compared with those from WKY in the older rats. However, stress-strain and incremental elastic modulus-stress relationships were similar between strains at all three ages. These data indicate that modifications of arterial wall mechanical properties do not contribute to these progressive arterial structural modifications.