With falling mortality rates for several diseases, patients are living longer with complex multimorbidities. We explored the burden of multimorbidity at the time of death, how it varies by socioeconomic status, and trends over time in Ontario, Canada. We calculated the proportions of decedents with varying degrees of multimorbidity and types of conditions at death, and we analyzed the trend from 1994 to 2013 in the number of conditions at the time of death. The prevalence of multimorbidity at death increased from 79.6 percent in 1994 to 95.3 percent in 2013. An upward trend in the number of conditions per person at death was observed for all chronic conditions except chronic coronary syndrome, congestive heart failure, and stroke. Chronic respiratory diseases and diabetes were disproportionately represented in low-income and deprived neighborhoods. The trend toward greater multimorbidity burden over time and the existence of steep socioeconomic gradients underscore the importance of integrated health care planning for preventing and managing multiple complex conditions.