Previous observational studies have reported the protective effect of β-blockers on the progression of different types of cancers. In 2011, we published a prospective study, including patients with histologically confirmed malignant melanoma in stage II–IIIA. In total, 25% of them reported previous use of β-blockers that were administered at any time for any other diseases. After a median follow-up of 2.5 years, 34% of the patients in the untreated group showed disease progression. In contrast, only 3% of the patients in the treated group showed progression. We report the findings obtained in the same cohort after a longer period of β-blocker therapy and follow-up (8 years). We prospectively reviewed data of the patients enrolled in the original prospective study. Disease progression was assessed by evaluating the presence of lymphatic, in-transit or visceral metastases. Deaths by any cause and deaths because of melanoma were recorded. A multivariate Cox proportional hazards model was used to evaluate the effect of β-blocker use on disease-free survival and overall survival, adjusting for significant confounders. After a median follow-up of 8 years and a median duration of β-blocker use of 7.6 years, 45% of the patients in the untreated group and 30% of the patients in the treated group showed disease progression. Notably, in the untreated group 35% patients died from melanoma and only 17% patients died from melanoma in the treated group. Results of this hospital-based prospective cohort study with a median follow-up of 8 years confirmed our previous results that the use of β-blockers significantly reduced the risk of recurrence and mortality in melanoma patients.