The present study aimed to examine the effects of 10-week dietary supplementation with silicon on free amino acid levels in egg yolk and on blood vessel strength in laying hens. We analyzed the levels of free amino acids in the yolk and white of eggs and blood vessel strength by high-performance liquid chromatography and tensile test, respectively. In initial experiments, 1% and 5% commercial product containing silicon had no effects on body weight, body weight gain, egg-laying rate, water intake, and food consumption relative to control. These data suggest that silicon intake at the evaluated concentrations was minimally toxic in the laying hens. The levels of aspartic acid, threonine, and alanine were significantly higher in the yolk of eggs laid by the hens receiving 5% dietary silicon product supplementation than in those laid by hens receiving 1% silicon product. In addition, blood vessel strength of the descending aorta was significantly higher in the 5% silicon product treated group than the control group. These results indicate that dietary supplementation with silicon might have beneficial effects on egg yolk taste and blood vessel strength in laying hens.