Severe uncontrolled chronic rhinosinusitis with nasal polyps (CRSwNP) is a challenging condition to treat. The European Position Paper on Rhinosinusitis and Nasal Polyps 2020 (EPOS2020) has the following criteria when considering biological therapy for severe uncontrolled CRSwNP: eosinophilia, need for oral corticosteroids (OCS), symptom score, loss of sense of smell and co-morbid asthma. This study aimed at finding associations of baseline factors with uncontrolled CRSwNP after endoscopic sinus surgery (ESS). Electronic health record data of CRSwNP patients (N = 137) undergoing ESS in 2002-17 were used. Endpoints of uncontrolled CRSwNP were revision ESS, purchased OCS and antibiotic courses during follow up. Baseline factors were chosen based on EPOS2020 and the data available: nasal polyp (NP) eosinophilia, peripheral blood eosinophilia, co-existing asthma and/or non-steroidal anti-inflammatory drug exacerbated respiratory disease (NERD), need for OCS during the previous year, previous ESS, endoscopic NP score, and Lund-Mackay score of sinus computed tomography scans. During the follow-up of 10.1 ± 3.1 (mean ± standard deviation) years, 35 (25.5%) individuals underwent revision ESS. The best predictive model was obtained by a sum of baseline (1) blood eosinophilia ≥ 250 cells/≥l and/or NP eosinophilia ≥ 30% (Eos), (2) asthma/NERD, and (3) ≥ 1 OCS/year. It was significantly associated with revision ESS, purchased doctor-prescribed OCS and antibiotic courses during follow-up. We identified similar predictive variables for uncontrolled CRSwNP that are used in the EPOS2020 indications of biological therapy, thus suggesting that these estimates are usable in clinical practice.