A positive test for β-hCG is used in clinical trials for pregnancy detection prior to entering the study and is indicated for women of a childbearing potential. Alternative causes of positive β-hCG test include postmenopausal state, pituitary production, and different malignancies. More caution is necessary if a woman has a malignant disease, as β-hCG may be a sign of the tumour under study, but at the same time, may be an early sign of a concurrent malignancy. A very limited number of publications have described positive β-hCG tests in non-Hodgkin’s lymphoma women patients of non-childbearing potential. In this article, Maxim Kosov, Nikolai Usachev, John Riefler and Maxim Belotserkovskiy at PSI CRO, describe three cases of positive β-hCG tests in women of non-childbearing potential due to non-Hodgkin’s lymphoma (NHL).