Background: The increased levels of visfatin in response to slowly developing resistance to insulin and impairment of glucose metabolism in human body is a well-documented process, beginning early in with uncontrolled diabetes and obesity The objective of present study was to determine the difference between levels of visfatin in the gestational diabetes mellitus cases and pregnancies with normal OGTT. Methods: It was a case control study conducted in Ayub Teaching Hospital Abbottabad. Twenty-eight (n=28) diagnosed cases of gestational diabetes mellitus at various gestational ages (ranging from 11 weeks to 33weeks of pregnancy) were included in the Group I and their levels were compared with non-diabetic normal antenatal cases, Group II (n=32). Blood samples were collected for blood glucose and visfatin levels. Visfatin levels were measured by enzyme-linked immunosorbent assay (ELIZA). Statistical analysis was performed on SPSS-20, and p<0.05 was taken as significant. Results: Pregnant women (n=60) of different gestational age ranging from 4–36 weeks of pregnancy when subdivided into three categories (4–12 weeks, 13–24 weeks, 24–36 weeks respectively), showed statistically significant (p=0.003) differences of serum visfatin levels (10.11±2.982, 1.01±2.634, 1.17±3.102 ng/ml respectively). There were no significant differences in mean value of serum visfatin (p=0.763) according to parity of the patients (0.16±2.892, 0.19±2.883, 1.01±2.736 respectively) in the three trimesters of pregnancy. Conclusion: Visfatin levels were significantly raised in gestational diabetes mellitus as early as first trimester of pregnancy. Increased levels of visfatin can be used as a novel biomarker for early detection of gestational diabetes mellitus. Pak J Physiol 2021;17(4):11?4