Aim: The purpose of this radiographic study was to evaluate the prevalence of intrabony defects and to study the correlation between these defects and clinical variables in a Swedish adult population. Another aim was to study the combined relationship of intrabony defects and furcation involvement with clinical variable. Materials and methods: The present study was performed using bitewing and apical radiographs from 329 subjects. The clinical and radiographic data were collected from the study that was carried out in Jonkoping 2003. Intrabony defects were measured from the bottom of the pocket to the highest point of alveolar bone crest. Furcations were considered healthy if the furcation was filled with bone up to the fornix. SPSS was used to analyze the results. Results: 2014 molars and 5898 non-molars were included in the study. The prevalence of intrabony defects was 2.2% in the whole population. Multivariate analysis showed that periodontal pockets (p <0.0001), plaque (p <0.001), age (p <0.02) and gender (p <0.03) had a significant relationship with the occurrence of intrabony defects. On the other hand, gingivitis, smoking habits and education level were not associated with intrabony defects. Multivariate analysis showed that the only variable associated with presence of intrabony defects and furcation involvement was presence of periodontal pockets (p <0.0001). Whilst, gingivitis, education level, plaque, gender, age and smoking habits were not associated with the outcome. Conclusions: Mandibular second molars were most likely to display intrabony defects, whilst mandibular incisors were the least likely to do so.