Objective: In a prospective study, we investigated the association between mid-trimester maternal serum AFP (ms-AFP), maternal serum hCG (ms-hCG) levels and adverse pregnancy outcome in a South-Western Greek population. Materials and Methods: 126 healthy Greek women with spontaneous pregnancies were investigated for ms-AFP and ms-hCG levels between the 13th and 24th weeks of gestation and followed for adverse pregnancy outcome. Abnormal outcomes were considered as ms-AFP levels or ms-hCG levels >2.0 multiples of the median value for gestation (MoM). Statistical analysis was performed by Pearson’s chi-square test. Results: Elevated ms-AFP levels were detected in a total of 25 out of the 126 women studied (19.84%). Elevated ms-hCG levels were detected in a total of ten of the 126 women studied (7.93%). Elevated ms-AFP and ms-hCG levels were detected in a total of four of the 126 women studied (3.17%). Conclusion: Multiparameter testing of placental function in the mid-trimester (uterine artery Doppler, placental morphology, ms-AFP and ms-hCG screening) may allow us to identify women with increased risk of developing severe placental insufficiency and pregnancy complications.