A number of genetic factors such as gender and hair colour have been associated with pain. ABO blood types have been linked to a diverse range of diseases such as various types of cancer, but only two studies have investigated a possible link between ABO blood types and pain. Thus, the aim of this study was to investigate if an association exists between a certain blood type and post-operative pain. Patients (18–40 years) who had an anterior cruciate ligament (ACL) reconstruction at Aalborg University Hospital, Aalborg, Denmark between January 2012 and August 2017 were included in this retrospective study. Blood type and postoperative analgesic use were extracted from the patients’ medical journals. The post-operative analgesics were converted to milligrams of morphine using equivalent doses for comparison between blood types and consumption of the analgesics. Sixty-six patients undergoing ACL reconstruction were divided into blood types A, B or O. None of the enrolled patients had AB blood type. No significant difference was found between a certain blood type and the amount of post-operative analgesics consumed (p=0.517). Findings from this study demonstrated that patients undergoing ACL reconstruction with blood types A, B and O were not significantly different concerning consumption of post-operative analgesics.