The most common indication for treatment with warfarin is the prevention of ischemic stroke in patients with atrial fibrillation. Time in therapeutic range (TTR) is an important tool to evaluate the quality of anticoagulation treatment. The aim of this study was to investigate the quality of treatment and the incidence of bleeding complications in patients on warfarin treatment treated by the anticoagulation clinic in Helsingborg. This is the first study that has specifically focused on the spontaneous reporting of bleeding complications in a real-world population. A total of 4,400 patients with a total of 8,394 patient years were registered, in the database Journalia AVK, during the time period November 1, 2007 to November 1, 2010. The mean age was 72 years. TTR was 73.3 % for the whole population. 421 patients suffered from haemorrhagic events. The frequency of major and fatal bleedings and intracranial haemorrhage (ICH) were 1.6, 0.2 and 0.5% per patient-year, respectively. A correlation between age and severe bleeding (major, fatal and ICH) (p = 0.003) was seen, but no correlation between gender and severe bleeding (p = 0.27). In 60 out of 455 bleeding events the complication had been reported to the anticoagulation clinic. At the anticoagulation clinic in Helsingborg the quality of warfarin treatment is good compared to previous results described in the literature, with regards to bleeding complications and efficacy. However, in our study, we confirm that the spontaneous reporting of bleeding complications related to warfarin is inadequate, and that review of patient records is needed to assure proper follow-up.