Background <p>Prediabetes is a reversible condition, and timely interventions can prevent long-term complications. Family support is crucial in managing this condition. This study evaluated the impact of a family health nurse (FHN) model for blood sugar control in middle-aged prediabetic individuals.</p> Method <p>This study adheres to the CONSORT 2010 statement guidelines. This study is a clinical trial involving 72 prediabetic middle-aged individuals from health service centers in Isfahan in 2023. The participants were selected through convenience sampling on the basis of the inclusion criteria and randomly assigned to the intervention or control groups. Data collection included a glucose meter, a calibrated scale, a demographic information form, and blood tests for HbA1c and fasting blood sugar (FBS). 15 training sessions based on the FHN model were conducted for the intervention group. Assessments were conducted before the intervention and three months later. The data were analyzed via SPSS _v26 with descriptive and inferential statistics.</p> Results <p>The research findings indicated no significant difference in FBS or HbA1c levels between the two groups before the FHN model was implemented (<i>P</i> &gt; 0.05). However, significant differences were observed immediately after the intervention and three months after the intervention (<i>P</i> &lt; 0.001). Results showed that the mean hemoglobin A1c score in the intervention group decreased from 5.41 mmol/L before the intervention to 5.27 mmol/L three months later (p value &lt; 0.05). In the control group, the mean score increased from 5.88 mmol/L to 6.05 mmol/L, but this change was not statistically significant (p value &gt; 0.05). These results highlight the potential of the family health nurse model to improve blood sugar control in prediabetic individuals.</p> Conclusion <p>This study indicates that a family-centered intervention using the FHN model can effectively enhance healthy lifestyle behaviors and blood sugar levels in prediabetic patients. These findings suggest that the model may be helpful for researchers and health practitioners, and we recommend its evaluation and implementation in broader communities.</p> Clinical trial registration <p>This research was registered (26/07/2023) in the <a href="https://www.irct.ir">https://www.irct.ir</a> with registration number: IRCT20230516058206N1).</p>