Death certificates are the source for mortality statistics and are used to set public health goals. Accurate death certificates are vital in tracking outcomes of cancer. Deaths may be certified by physicians or other medical professionals, coroners, or medical examiners. Idaho is one of 3 states that participated in a Centers for Disease Control and Prevention-funded study to assess the concordance between cancer-specific causes of death and primary cancer site among linked cancer registry/death certificate data. We investigated variability in the accuracy of cancer death certificates by characteristics of death certifiers, including certifier type (physician vs coroner), physician specialty, years of experience as death certifier, and number of deaths certified. This study showed significant differences by certifier type/physician specialty in the accuracy of cancer mortality measured by death certificates. Nonphysician coroners had lower accuracy rates compared with physicians. Although nonphysician coroners certified less than 5% of cancer deaths in Idaho, they were significantly less likely to match the primary site from the cancer registry. Results from this study may be useful in the future training of death certifiers to improve the accuracy of death certificates and cancer mortality statistics.