Periodontal disease is multifactorial, in terms of potential etiological factors and modifiers of achieved therapeutic effects. The wide spectrum of positive therapeutic reflections in the periodontal-tissue complex achieved by laser therapy represents a challenge for the application of this modality in the modern therapy of periodontal disease. The objective of this study was to evaluate the clinical results of the application of laser therapy with diode laser, as an additional therapeutic method to conventional periodontal treatment in smoking and non-smoking patients. Therefore verification of the anti-inflammatory influence of the laser light and the effects of the application of laser therapy with a diode laser were the main points of this study. A comparative analysis was made between the studied groups. The study was conducted on 60 patients with periodontal disease divided into four groups: two groups of smokers and two groups of non-smokers. A conventional periodontal therapeutic procedure was carried out in all subjects, and then in half of the subjects the treatment was supplemented with laser therapy (diode laser). The evaluation of the clinical results was done using the following indices: 1. Evaluation of gingival inflammation through the index of Loe and Silness and 2. Assessment of the presence of periodontal pocket bleeding, during probing, through the index of bleeding according to Loe and Silness. The obtained results showed a positive clinical evaluation in patients treated with diode laser, as an additional therapeutic method, compared to those who received conventional treatment. The comparative analysis carried out between patients who smoke and those who do not smoke, the positive clinical evaluation i.e. positive clinical effects were evaluated in non-smokers.The application of laser therapy with a diode laser as an additional method to conventional periodontal treatment gives good clinical results, reduces relapses and maintains therapeutic results for a longer period of time.