BACKGROUND: Smoking and alcohol use impair post-operative outcomes. However, no studies include fast-track surgery, which is a multimodal-enhanced recovery programme demonstrated to improve outcome. We hypothesised that outcome is similar in smokers and alcohol users as in non-users after fast-track hip and knee arthroplasty. METHODS: Prospective questionnaires on co-morbidity and smoking/alcohol use were cross-referenced with the Danish National Health Registry to investigate relationship between smoking/alcohol use and length of stay of > 4 days and readmissions ≤ 90 days after fast-track hip and knee arthroplasty. RESULTS: In 3041 consecutive patients, 458 reported smoking and 216 drinking > 2 drinks a day, of which 66 did both. Smokers/alcohol users were younger than non-users (mean age: 64.3 vs. 68.0 years, P  4 days and smoking (odds ratio [95% confidence interval], P) (1.34 [0.92-1.95], 0.127) or alcohol use (0.59 [0.30-1.16], 0.127). Thirty- and ninety-day readmission rate was 6.6% (n = 201) and 9.4% (n = 285). Multiple logistic regression analysis showed an increased risk of readmissions in smokers at 30 (1.60 [1.05-2.44], 0.028) but not 90-day follow-up (1.17 [0.80-1.73], 0.419). No increased risk of readmissions was found in alcohol users at 30 (0.94 [0.50-1.76], 0.838) or 90-day follow-up (0.83 [0.47-1.49], 0.532). No increased risk of specific readmissions (i.e. wound infections or pneumonia) typically related to smoking/alcohol use was found in smokers (1.56 [0.93-2.62], 0.091) or alcohol users (1.00 [0.47-2.15], 0.999) at 90-day follow-up. CONCLUSION: Influence of smoking or alcohol use may be less pronounced in fast-track hip and knee arthroplasty compared with data with conventional care programmes.