Background Patients affected by ulcerative colitis (UC) are more likely to develop colorectal cancer, and are often diagnosed with lymph node involvement (N+) at surgery. Aim To identify the risk factors for N+ cancer in UC patients. Methods Patients undergoing surgery from 2001 to 2018 in six European tertiary centres were included. N+ patients were compared to the control group (N−) for clinical variables. The evaluation of risk factors for N+ was assessed using univariate and multivariable logistic regression analyses. Results A total of 130 patients were included. Median duration of disease was 21 years (1–52). Forty patients (30.8%) were N+ at surgery. Eighteen (13.8%) developed cancer within 10 years from the onset of UC. Younger age at surgery (Odds ratio -OR- 0.96, p = 0.042), left colon location (OR 2.44, p = 0.045) and the presence of stricture (OR 5.07, p = 0.002) were associated with N+. Conclusion Location in the left colon, presence of strictures and younger age strongly correlated with a higher risk of N+ cancer, which could develop before the starting point of surveillance. Duration, extension and severity of disease were not associated with N+. These results should be considered in the evaluation of risk of advanced cancer in UC patients.