From January, 1979, to July, 1986, 10 patients (6 females, 4 males; 12–59 years, mean 37) with colloid cysts of the third ventricle were treated by stereotactic aspiration (Talairach''s method). Five cysts have been completely aspirated. The mean residual volume of the other 5 was 19% of the initial volume. Clinical symptoms completely cleared in all but one patient. The advantages of the procedure are discussed.