Objective: To review contemporary knowledge of the hCG molecule, its isoforms and the importance of glycosylation. Biologic variants and glycoforms of hCG have different biological activities and functions related to the control of menstrual cycle, conception, gestation as well as gynaecologic and non-gynaecologic malignancies. Design: A review. Setting: Department of Obstetrics and Gynaecology, University Hospital Olomouc. Methods: To present own experience and an overview of recent literature in molecular biology, clinical biochemistry and clinical practice. Conclusion: Recent knowledge of the role of hCG glycosylation in physiologic and pathologic events in female organism will provide a better understanding of regulation of processes like ovulation (co-operation of pituitary hCG with LH), implantation and hemochorial placentation (invasivity of hyperglycosylated hCG). Some biologic variants and isoforms of hCG are important for the prediction of certain pathologies of pregnancy, prenatal screening of inborn errors (free beta hCG) as well as in the treatment of infertility.