Cancer is an important public health problem. Prostate cancer is one of the most common cancers among men. In Poland, the incidence of this type of cancer is constantly growing. Considering the appearance of a new coronavirus in December 2019 (SARS-CoV-2) and the fact that oncology patients, including those with prostate cancer, are particularly vulnerable to infection, it is recommended to get vaccinated against COVID-19. In our study, we determined the level and prevalence of antibodies against SARS-CoV-2 IgG in patients with prostate cancer compared to the control group and whether the patients' ages affected the level of antibodies. PCa patients and controls were divided into two age groups: 50-59 years and 60-70 years. We also analyzed the level of antibodies in patients belonging to the relevant risk groups for prostate cancer (the European Society of Urology risk group classification of prostate cancer). For the study, we used the Microblot-Array COVID-19 IgG test to detect antibodies against the three main SARS-CoV-2 antigens: NCP, RBD, and S2. Our results showed that prostate cancer patients had significantly lower levels of anti-SARS-CoV-2 IgG antibodies compared to controls. In addition, age also affected the decrease in the number of IgG antibodies. The level of antibodies in the intermediate/high-risk group was lower compared to the low-risk group.