Gender bias in medicine is typically discussed in terms of disadvantages for women. However, in Chronic Kidney Disease (CKD), differences in screening habits and GFR estimation formulas might lead to different patterns of underdiagnosis between sexes.To compare the rate of clinical diagnosis (coding) of CKD between men and women who meet the same objective laboratory criteria for the disease.Observational study on 988 patients. We selected all patients meeting KDIGO analytical criteria for CKD (GFR < 60 or ACR ≥ 30). We calculated the "diagnosis rate" (percentage of these patients who actually had a CKD code in their electronic health record) and compared it by gender using descriptive statistics.Sixty-nine patients met the analytical criteria for CKD (42 men and 27 women). Interestingly, women were significantly more likely to be correctly diagnosed (55.6% diagnosis rate) compared to men, of whom only 38.1% had a recorded diagnosis. This occurred despite men and women having similar mean GFR levels (63.9 vs 67.1 ml/min) and albuminuria profiles.Our data reveals a "reverse gender gap" in CKD recognition, where men with renal insufficiency or albuminuria are less likely to be coded as CKD patients than women. This could be related to more frequent healthcare contact by women or a lower perception of fragility in male patients by clinicians.In our setting, men with objective renal damage suffer from a significantly higher rate of underdiagnosis (61.9%) compared to women. Strategies to improve CKD coding should specifically target the male population to ensure they receive adequate follow-up and preventive care.