The paper presents a classification of tall stature and clinical and hormonal findings in 35 girls in the age range of 11 to 18 years with constitutional tall stature. They showed a normal decline in growth hormone (GH) concentrations in the second phase of pubertal maturation. Concentrations of GH clearly correlated with the menstrual status. They were low in regularly menstruating girls, higher in non-menstruating girls and highest in tall girls with irregular menstrual cycles. Estrogen therapy in 7 girls decelerated growth rates and promoted epiphyseal ossification. Regular menstrual cycles established after withdrawal of therapy in all patients.