The disease phenotype at diagnosis and the disease course of Crohn's disease (CD) and ulcerative colitis (UC) show remarkable heterogeneity across patients. In recent population-based epidemiological and referral cohort studies, the evolution of disease phenotype of CD and UC varied significantly. Most CD and severe UC patients still requires hospitalization or surgery/colectomy during follow-up. A change in the natural history of IBD with improved outcomes in parallel with tailored positioning of aggressive immunomodulator and biological therapy has been suspected according to the recently available literature. Therefore it is of major importance to refer IBD cases at risk for adverse disease outcomes as early during the disease course as possible. This review aims to summarize the currently available evidence on clinical and some environmental predictive factors, which clinicians should evaluate in the everyday practice together with other laboratory and imaging data to prevent disease progression, enable a more personalized therapy, and avoid negative disease outcomes.