The association of myopia and height, weight and body-mass index was examined by two methods: a case control method and a co-twin control method. One hundred eightyseven myopic (57 males and 130 females) and 603 non-myopic (335 males and 268 females) subjects were studied in the first study. Among males the myopic subjects were taller compared to the non-myopic subjects (P less than 0.05). Among females such difference could not be found. Weight was not statistically significantly different in these two groups in either sex. When the myopic twin partners were compared to the non-myopic co-twins, a statistically significant difference in body mass index could again be noticed among males (P less than 0.01) but not among females. The difference in social class did not explain the previous associations.