Cancer during pregnancy is a challenge for multi- and interdisciplinary collaboration due to the diagnostic, prognostic and therapeutic implications, the need for an integrated harmonization of medical action for the pregnant patient and the embryo or foetus and the characteristics of each gestational period, which will determine the protocol to be proposed and its limitations. For this reason, a group of experts appointed by participating scientific societies, which includes the Spanish Society of Medical Oncology (Sociedad Española de Oncología Médica-SEOM), the Spanish Association of Surgeons (Asociación Española de Cirujanos-AEC), the Spanish Society of Gynaecology and Obstetrics (Sociedad Española de Ginecología y Obstetricia-SEGO), the Spanish Society of Nuclear Medicine and Molecular Imaging (Sociedad Española de Medicina Nuclear e Imagen Molecular-SEMNIM), the Spanish Society of Oncological Radiotherapy (Sociedad Española de Oncología Radioterápica-SEOR) and the Spanish Society of Medical Radiology (Sociedad Española de Radiología Médica-SERAM), have worked together to establish consensus recommendations that allow the harmonization of management and ultimately the optimization of the healthcare of pregnant patients with cancer. When cancer is detected in a pregnant woman, the week of gestation in which the diagnosis is made must be considered, as well as the characteristics of the tumour. It is strongly recommended that a multidisciplinary team assesses the situation and guides the patient and her family during the informing, diagnosis and treatment process. Likewise, the foetus should be monitored and managed by specialized obstetricians who are part of a multidisciplinary cancer committee.