Objective: To identify low prognosis in-vitro fertilization (IVF) patients treated at Centro de Fertilidad y Ginecologia del Sur (CFGS) based on the POSEIDON criteria. Methods: This retrospective study included 412 IVF patients and assessed them based on the POSEIDON criteria to describe the cumulative live birth rates seen in each group. Results: 13.1% of patients met the POSEIDON criteria, and the proportion of cases in POSEIDON groups 1, 2, 3 and 4 were 20.4%, 31.5%, 14.8%, and 33.3%, respectively. The cumulative live birth rate for the individuals meeting the POSEIDON criteria was 25.9%, while for patients in POSEIDON groups 1, 2, 3, and 4 the rates were 45.5%, 29.4%, 25.0%, and 11%, respectively. The differences were not statistically significant due to the small number of cases. Conclusions: Patients belonging to the four POSEIDON groups were described at CFGS. Age and number of retrieved mature oocytes were determining parameters in the prognosis of pregnancy in IVF/ICSI patients.