Objective: We aimed to investigate the relationship between Onodera's prognostic nutrition index (OPNI) and controlling nutritional status index (CONUT) that are used for evaluating the nutritional status and late-onset fetal growth restriction (FGR). Material and Methods: This study was a prospective cross-sectional study on 141 patients, which was conducted at the Medical Faculty of Selcuk University. The study included 62 women with late-onset FGR and 79 control patients. The control group was randomly selected from among pregnant women in the 32nd-37th gestational weeks with pre-pregnancy body mass index (BMI) <25 kg/m2, without any systemic and metabolic disease, without substance use such as alcohol, cigarettes, and without the use of any drugs. The OPNI and CONUT values for each patient were measured within 3 days prior to the delivery. Results: Age, gravida, parity, and birth week were similar between the groups (p>0.05). Before birth and pre-pregnancy weight, height, and pre-pregnancy BMI were significantly different between the groups (p<0.05). Considering the mode of delivery among the groups, the vaginal birth rate was higher in the control group (67.1% vs. 32.9%), and the cesarean section rate was higher in patients with late-onset FGR (58.1% vs. 41.9%). Neutrophil-lymphocyte ratio and OPNI values were similar between the groups (p>0.05). We classified the CONUT score calculation according to two different cut-off values, and both classifications were similar between the groups (p>0.05). Conclusion: It has been shown that the OPNI and CONUT scores, which are used to predict nutritional status and prognosis in cancer and chronic diseases, are not useful to predict the late-onset FGR.