This study investigates the self-management capabilities of Persons Who Use Drugs (PWUDs) with multimorbidity in the Philippines, focusing on the Department of Health-Drug Treatment and Rehabilitation Center in Dagupan City, a 300-bed facility. It aims to enhance understanding of effective healthcare support strategies in this complex context. Specific objectives include exploring multimorbidity prevalence, evaluating self-management practices across seven domains, and exploring cultural factors and self-management practices among PWUDs. The study utilised a Retrospective Chart Review (RCR) to analyse existing patient data from the Department of Health-Drug Treatment and Rehabilitation Center in Dagupan, focusing on male PWUDs aged 18–59 with multimorbidity. Data collection included chart reviews and interviews with clinical professionals to establish study protocols. Descriptive statistics and generalized linear models were applied to analyse self-management across seven domains, offering insights into chronic care strategies for PWUDs. Descriptive statistics provide insights into self-management capacity across diverse healthcare settings, highlighting multimorbidity prevalence and proactive self-management strategies. The study concludes with recommendations for integrated interventions, collaborative approaches, and targeted strategies for PWUDs facing multimorbidity challenges, aligning with future healthcare trends and offering insights from an Asian country perspective.