Background Different biomarkers are detectable in cases of chronic rhinosinusitis with nasal polyposis (CRSwNP) with need for evaluation of their diagnostic and prognostic roles. Objective To assess the serum levels of total IgE, interleukin-17 and Pentraxin-3 in patients with CRSwNP and correlate them with the clinical evaluation using Sino-Nasal Outcome Test (SNOT-22), radiological evaluation using Lund – Mackay (LM) computed tomography scan score, and polyposis recurrence. Methods This cross-sectional comparative study was carried out on fifty patients with CRSwNP and twenty-five age and gender matched healthy volunteers as control group. Patients were assessed clinically by SNOT-22 and radiologically by LM score. Blood samples of patients and controls were analyzed for serum levels of total immunoglobulin E (IgE), Interleukin-17 (IL-17) and Pentraxin-3 (PTX-3). The correlation between the serum levels of every two markers of the study markers was assessed. The levels of the three biomarkers were correlated with SNOT-22 and LM scores and polyp recurrence with assessment of their sensitivity and specificity to diagnose CRSwNP. Results This study showed significantly higher values of the three biomarkers in patients group compared with control group (p < 0.001 for all). There were significant positive correlations between the levels of the three markers and SNOT 22 and LM scores (p < 0.001 for all) and with recurrence of polyposis (p < 0.001, p = 0.005 and p = 0.032 respectively). Agreement (sensitivity and specificity) for these markers to diagnose patient group was statistically significant (p < 0.001 for all). There was a significant positive correlation between every two markers of the study markers. Conclusion Serum levels of total IgE, IL-17 and PTX-3 are important biological markers for diagnosis and follow up of cases of CRSwNP with high sensitivity and specificity in detection of such cases. They should be included in the routine laboratory workup for cases of CRSwNP.