Objective To understand the defense status of glandular tissue in the human adult larynx, we examined the glandular distribution, concentration and the ratio of the mucous glands in the subglottic and supraglottic larynx. Methods One-hundred and seven adult larynges were examined. The area of the mucosa and glands were measured using an image analyzing system. The correlations of the concentration as well as the ratio of the mucous glands with age were analyzed. Results The ratio of the areas occupied by the glandular acini of the subglottis was almost equal to that of infants as we reported earlier. The concentration of the laryngeal glands decreased in higher-aged adults at the level of the supraglottis, but not at the level of the subglottis. Conclusions In comparison to infants, the ratio of laryngeal glands of the human subglottic larynx is rather constant in human adults. However, the supraglottic larynx seems to be influenced by increasing age. The changes deserved in the laryngeal glands predominantly occur in the supraglottic larynx.