Preterm premature rupture of membranes (PPROM) is defined as a spontaneous membrane rupture that occurs before the onset of labor and 37 weeks gestation. Subclinical intrauterine infection has been suggested as a very important etiological factor in the pathogenesis and subsequent morbidity related with PPROM. This study was performed to assess the levels of maternal proadrenomedullin (pro-ADM) and serum amyloid A (AA) in PPROM and its association with fetomaternal infectious morbidity. A total of 63 pregnant women, of which 43 with PPROM between 24 and 34 weeks gestation and 20 normal pregnant women without PPROM were included in the study. The study group was separated into 2 subgroups as PPROM and PPROM-histological chorioamnionitis (PPROM-HC). The blood samples were taken before the administration of any medication. The mean serum interleukin-6 (IL-6), AA, and pro-ADM values in the PPROM-HC group were significantly higher than the PPROM and control group. The cutoff values of pro-ADM and AA were determined as 4.2 nM and 69 μg/mL, respectively. Both of them showed similar sensitivity, specificity to IL-6 and a better sensitivity and specificity as compared to C-reactive protein and white blood cell count. We determined the predictive value of pro-ADM and serum AA measurements in PPROM and PPROM with histological chorioamnionitis. We suggest using pro-ADM and serum AA biomarkers for detecting the histological chorioamnionitis at an earlier stage in PPROM without any clinical signs.