WHAT IS KNOWN ON THE SUBJECT? : Dual diagnosis is one of the leading causes of disability globally. Consumers with dual diagnosis have complex needs and are at risk of relapse of their psychiatric symptoms. Mental health nurses require essential skills, including empathy, to manage consumers with dual diagnosis. No studies have explored mental health nurses' empathy towards consumers with dual diagnosis. WHAT DOES THE PAPER ADD TO EXISTING KNOWLEDGE? : Developing empathy towards consumers with dual diagnosis is complex. Mental health nurses' unemotional empathy experiences with consumers with dual diagnosis are related to their lack of ability to connect to their consumers' choices and feelings. Negative attitudes towards consumers with dual diagnosis contributed to nurses' poor empathy experiences. The unemotional responses of mental health nurses can be caused by factors such as novelty, insufficient information, and neutral evaluation of a consumer's situation. WHAT ARE THE IMPLICATIONS FOR PRACTICE? : The study results benefit researchers, teachers, clinicians, and administrators when designing, developing, and delivering empathy training packages for mental health nurses. Improving the empathy of mental health nurses towards consumers with dual diagnosis should be a top priority for healthcare leaders and educators. A core curriculum containing holistic awareness of the biopsychosocial components of dual diagnosis makes it easier for mental health nurses to understand and develop empathy towards consumers with dual diagnosis. Future studies must address the relationship between attitude, stress, burnout, compassion fatigue and empathy among mental health nurses in relation to consumers with dual diagnosis. INTRODUCTION: There is a lack of evidence regarding mental health nurses' empathy towards consumers with dual diagnosis. This qualitative study aimed to describe mental health nurses' empathy towards consumers with dual diagnosis in Australian mental health settings. Through purposeful sampling, interviews were conducted with 17 mental health nurses who have experience in caring for consumers with dual diagnosis. Thematic analysis, as an inductive approach was used, to generate codes and themes from participant data. To report on this qualitative study, we adhered to the ENTREQ guidelines. Four themes emerged: challenges to develop empathy with consumers, lack of conducive attitude of nurses towards consumers, appraising consumers' emotions accurately and holistically responding to the appraised emotions. The findings indicated that developing empathy towards consumers with dual diagnosis is a complex task. Mental health nurses may struggle to empathize with consumers when encountering confrontational situations. Interventional studies are required to address the relationship between mental health nurses' attitudes, stress, burnout, compassion fatigue and empathy in relation to consumers with dual diagnosis. Understanding why mental health nurses emotional experiences differ about a similar challenging situation experienced by their consumers is vital. Further research on strategies to address empathy issues among mental health nurses could enhance nursing practice and consumer care.