Diabetes mellitus (DM) is a chronic metabolic disease characterised by persistent hyperglycemia. The etiology of the condition could stem from issues related to insulin secretion, peripheral insulin resistance, or a combination of both factors. Slow deep breathing (SDB) is abdominal breathing with a slow or slow frequency, rhythmic and comfortable which is done by closing the eyes and blowing air through the lips. SDB technique is done for 15 minutes 3 times a day, can be accomplished at any time. It is anticipated that there will be a globally recognised standard for Sleep-Disordered Breathing (SDB) procedures. This will facilitate further research utilizing larger sample sizes for more robust analysis. Aims: to detect the effect of the application of SDB to DM Type II patient experiencing anxiety during the treatment at Royal Prima Hospital. Study design: the chosen design was a quasi experiment with a case study with the use of the SPSS. The sample size comprised a singular participant meeting the criteria of Type 2 Diabetes Mellitus (DM) accompanied by comorbid anxiety and undergoing treatment for a duration exceeding 48 hours. Data collection methods encompassed interviews, interventions, observations, documentation, and subsequent evaluations. Place and Duration of Study: Royal Prima Hospital and 1 month Methodology: quantitative methods were employed, adhering to ethical guidelines that included obtaining informed consent from participants who agreed to partake as respondents. Results: after SDB intervention the blood pressure was reduced from the first examination, and the period of sleep from 4 to 6-8 hours, the patient's anxiety was reduced as well as the dizziness. The patient exhibited a noticeable reduction in signs of tension. Conclusion: Slow Deep Breathing (SDB) can reduce anxiety in DM Type II patients.