Chronic rhinosinusitis with nasal polyps (CRSwNP) often requires surgery, but recurrence even after surgery is common. Recurrence rates largely vary in literature and asthma seems to be a comorbid factor. In this study, we aim to estimate disease recurrence during a long-term follow-up, together with the investigation of possible predicting and/or influencing parameters. Out of 196 patients operated for CRSwNP between 01/2000 and 01/2006, 133 patients had a follow-up of at least 10 years and could be included. The inflammatory profile at surgery was determined on nasal tissue and sinonasal secretions, and included analysis of eosinophils, eosinophilic-rich mucus (ERM) typically containing Charcot-Leyden crystals (CLC), and fungal hyphae (FH). During follow-up, recurrence, received treatments and comorbidities were collected. Out of the 133 included patients, local eosinophilia was present in 81% and ERM in 60%. Recurrence during follow-up was observed in 62%, and was associated with local eosinophilia and ERM (both p < 0.001). Asthma was present in 28% at inclusion, and 17% developed asthma after surgery during follow-up. The presence of asthma, at inclusion as well as developed during follow-up, was significantly associated with recurrence of CRSwNP (p = 0.001 for group comparison). Recurrence after CRSwNP surgery is common when a long-term follow-up is taken into account. ERM detected in sinonasal secretions at surgery seems to be a predictive factor for recurrence and need for revision surgery. Asthma is a frequently found comorbid factor in CRSwNP, develops even at higher age despite surgical treatment for CRSwNP, and is also associated with a higher recurrence rate. Sustained medical care after surgery is mandatory.