Aim: Progesterone (P4) rise on the day of the trigger is often regarded as a poor prognostic factor in assisted reproductive technology (ART) cycles. We aimed to identify the utility of the progesterone/estradiol (P4/E2) ratio as a predictor of pregnancy outcome in the subgroup of patients with P4 elevation. Materials and methods: We conducted a prospective study on women with normal basal hormonal parameters who underwent ART utilizing the long downregulation protocol. Serum P4 and E2 were assayed on the day of the trigger. The role of P4 elevation and the role of the P4/E2 ratio in those with elevated P4 were analyzed with respect to ART outcome using the t-test and Mann–Whitney U test. Receiver operating characteristic (ROC) curve analysis was done to identify a cutoff value of the P4/E2 ratio below which a good prognosis could be predicted. Results: We included 422 patients. The pregnancy rate was 42.4%. Elevated P4 > 1.5 ng/mL was seen in 20.4%. The P4/E2 ratio was higher in nonpregnant patients when compared to pregnant patients and was statistically significant (0.56 ± 0.81 vs 0.4 ± 0.61 and p = 0.001). The cutoff value for P4/E2 ratio by ROC curve analysis was 0.463, with a negative predictive value of 69.6%. Those with elevated P4 > 1.5 ng/mL and P4/E2 ratio >0.463 had a significantly lower pregnancy rate than those with normal (<1.5 ng/mL) P4 levels (45.4% vs 32%, and p = 0.03). Conclusion: Progesterone/estradiol (P4/E2) assay on the day of human chorionic gonadotropin (HCG) assumes significance in predicting pregnancy outcomes in patients undergoing ART, especially those with elevated P4 levels. If the P4 level is high on the day of HCG, it is better to see P4/E2 ratio before the routine cancellation of the transfer. Clinical significance: The clinical practice of freezing all the embryos in those with elevated P4 on the day of the trigger could be restricted to only those with elevated P4/E2 ratio also.