Alcohol intoxication appears to be a contributing factor to many bicycle crashes with serious consequences. Despite this, there is no specific limit on the blood alcohol concentration permissible when cycling in Sweden, and there is very little knowledge of the perception of sobriety associated with cycling. The aim of this study is therefore to identify the behavioural, normative, and control beliefs underpinning cyclists’ attitude, subjective norm, and perceived behavioural control associated with riding a bicycle when mildly alcohol intoxicated. A total of 34 participants answered questions based on the theory of planned behaviour (Ajzen, 1991). The results indicate that the participants saw great advantages (practical, free, safe, nice, and better than taking the car), but also disadvantages (impaired ability, danger to oneself, and danger to others) from cycling when mildly alcohol intoxicated. Furthermore, they identified both factors making it easier (small amounts of alcohol, bicycle-friendly infrastructure/conditions, poor alternatives, group pressure, and emergency situations) and more difficult (large amounts of alcohol, aggravating circumstances, bicycle-unfriendly infrastructure/conditions, good alternatives, social censure, group resistance, parenthood, and experience) to opt to cycle when mildly alcohol intoxicated. Finally, some participants believed that certain people (e.g. students, people with poor finances, and nearly everyone) think that it is acceptable to cycle when mildly alcohol intoxicated, while others (e.g. parents, responsible people, and nearly no group) think that it is unacceptable. These results support the use of information dissemination/campaigns to reduce the incidence of cycling when alcohol intoxicated and/or the amount of alcohol consumed in connection with cycling. At the same time, they do not support the introduction of a specific limit on the blood alcohol concentration permissible when cycling, and the potential of improved public transport to reduce the number of inebriated cyclists is uncertain.