High alcohol consumption is related to colorectal cancer (CRC). Our objective was to study associations between alcohol consumption and risk of CRC according to characteristics of aetiological pathways: the chromosomal instability (CIN) and the microsatellite instability (MIN) pathway. We classified CIN+ tumours (tumours with either a truncating APC mutation, an activating K-ras mutation or overexpression of p53), MIN+ tumours (tumours lacking hMLH1 expression) and CIN− /MIN− tumours (tumours without these defects). In the Netherlands Cohort Study on diet and cancer, 120 852 men and women, aged 55–69 years, completed a questionnaire on risk factors for cancer at baseline (1986). Case–cohort analyses were conducted using 573 CRC cases with complete data after 7·3 years of follow-up, excluding the first 2·3 years. Adjusted incidence rate ratios (RR) and 95 % confidence intervals (CI) were estimated. Compared with abstaining, alcohol consumption of ≥ 30 g/d was positively associated with the risk of CRC irrespective of genetic or molecular aberrations present, although statistical significance was not reached (RR 1·35 (95 % CI 0·9–2·0) for the CIN+ tumours, RR 1·59 (95 % CI 0·4–5·8) for the MIN+ tumours and RR 1.15 (95 % CI 0·5–2·7) for the CIN− /MIN− tumours). Beer, wine and liquor consumption were, independent of their alcoholic content, not consistently associated with the risk of CRC within the defined subgroups. In conclusion, our results indicate that a daily alcohol consumption of ≥ 30 g is associated with an increase in risk of CRC, independent of the presence or absence of the studied characteristics of different aetiological pathways.