Oral lichen planus (OLP) is a chronic inflammatory disease that is frequently detected in oral tissues. The aim of our study was to identify the prevalence of the detection of periodontopathogenic microorganisms (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia and Treponema denticola in OLP patients and to compare with this prevalence of periodontopathogenic microorganisms in healthy non-OLP patients. Our study included 27 (18 chronic periodontitis (OLPP) and 9 gingivitis (OLPG)) patients diagnosed with OLP along with 26 (13 chronic periodontitis (HP) and 13 gingivitis (HG)) healthy non-OLP patients. The multiplex polymerase chain reaction (PCR) with subsequent reverse hybridization method (micro-IDent) was used for identifying periodontopathogenic microorganisms present in subgingival plaque samples. The percentages of detection for A. actinomycetemcomitans, P. gingivalis, P. intermedia, T. forsythia and T. denticola in subgingival plaque samples taken from OLP patients (OLPG and OLPP) were 18.5%, 85.1%, 81.4%, 88.8% and 74%, respectively. Meanwhile, in the non-OLP patients (HG and HP), these values were 7.6%, 50%, 46.1%, 73% and 57.7%, respectively. Thus, comparing the non-OLP groups with the OLP groups, the periodontopathogens' percentages of detection in the OLP groups were higher than those in the non-OLP groups. According to our study results, OLP patients have higher levels of infection with A. actinomycetemcomitans, P. gingivalis, P. intermedia, T. forsythia and T. denticola than non-OLP patients. We argue that the high percentages in patients with OLP may help identify the importance of periodontopathogenic microorganisms in the progress of periodontal diseases of OLP. © 2013 WCSS. All rights reserved.