Plasmatic Human Chorionic Gonadotropin (hCG) was studied in 41 patients undergoing salpingectomy for tubal pregnancy. On the temporal scale of our research, a biexponential model proved to be adequate to describe hCG clearance; the combined reading of the results of this research and those of other Authors have led us to maintain that hCG clearance is characterised by at least three components. HCG clearance was faster in patients with a higher initial hCG. Nevertheless the problem of hCG clearance depending on its initial value remains unsolved and requires further investigation. The regression curve and relative hCG values obtained in this study can be used as reliable models of comparison in the monitoring of patients undergoing conservative surgical treatment of tubal pregnancy.