Purpose: A pre-licensure clinical trial of a two-dose cytosine phosphoguanine adjuvanted hepatitis B vaccine (HEPLISAV-B® [Dynavax, USA]; HepB-CpG vaccine) found an unanticipated numerical imbalance in acute myocardial infarction (AMI) compared to recipients of a three-dose aluminum adjuvanted hepatitis B vaccine (ENGERIX-B® [GlaxoSmithKline, Belgium]; HepB-alum vaccine). A post-licensure study was required to compare AMI rates among recipients of HepB-CpG vaccine and HepB-alum vaccine. Individuals with diabetes mellitus (DM), who are at higher risk of AMI, comprise more than half of the post-licensure study cohort. To inform the ongoing post-licensure study, we examined the association between AMI and receipt of HepB-alum vaccine in individuals with DM. Methods: We conducted a case–control study nested in a cohort of individuals with DM ages ≥40 years at Kaiser Permanente Southern California using electronic health records. AMI cases from 2012 to 2017 were identified by principal discharge diagnosis and matched 1:1 with randomly selected controls. The adjusted odds ratio (aOR) for receipt of ≥1 HepB-alum vaccine dose was compared for AMI cases and controls using conditional logistic regression. We subsequently performed the same matched case–control analysis stratified by year. Results: Of 8138 matched case–control pairs, 17.4% of cases and 15.0% of controls received HepB-alum vaccine. The aOR of HepB-alum vaccination comparing cases and controls was 0.97 (95% confidence interval 0.87–1.08). Similarly, there was no significant association between HepB-alum vaccine and AMI in any of the study years. Conclusions: HepB-alum vaccination was not associated with AMI in individuals with DM. This finding will provide contextual insight for the ongoing post-licensure study of HepB-CpG vaccine.