Background: We aimed to compare the cerebral fissure depths in isolated mild-moderate ventriculomegaly fetuses and healthy fetuses according to gestational weeks using magnetic resonance imaging. Method: A total of 203 fetuses were included in our study. While 77 fetuses had normal fetal MRI reports and were included in the control group, 126 fetuses had isolated mild-moderate ventriculomegaly and were included in the patient group. All measurements were performed by two clinicians, a radiologist and a perinatologist. Results: In the study, parieto-occipital fissure and calcarine fissure depths of the isolated mild-moderate ventriculomegaly group were significantly lower than the control group (p < 0.001, p < 0.001, respectively). Significant negative correlation was observed between ventricular width and parieto-occipital fissure and calcarine fissure depth. In our study, the intraclass correlation coefficient values of the agreement between the two experts were found to be 0.995 for calcarine fissure, 0.996 for parieto-occipital fissure, 0.990 for lateral ventricle width, and it was found to be perfect agreement. Conclusion: Although the potential of cerebral fissure depths as a predictive marker for postnatal developmental problems has not yet been established, we believe that underdevelopment of these fissures in isolated mild-moderate ventriculomegaly fetuses may be an additional indicator of developmental abnormalities.