To describe 2008 Florida sleep-related sudden unexpected infant deaths (SUIDs) by describing (a) percentage distribution of medical examiner (ME) cause-of-death determinations; (b) mortality rates by maternal and infant characteristics; (c) prevalence of selected suffocation or sudden infant death syndrome (SIDS) risk and protective factors; (d) frequency of selected scene investigation and autopsy components (including extent of missing data); and (e) percentage with public health program contact. In this population-based study, we identified sleep-related SUIDs occurring among Florida residents from the 2008-linked Florida infant death and birth certificates. Information about the circumstances of death was abstracted from ME, law enforcement, and hospital records. We used frequencies and percentages to describe characteristics of sleep-related SUID cases. Of 215 sleep-related SUID cases, MEs identified 47.9% as accidental suffocation and strangulation in bed, 35.4% as unknown or undetermined cause, and 16.7% as SIDS. Sleep-related SUID most frequently occurred in an adult bed (n = 108; 50.2%). At death, 82.4% of sleep-related SUIDs had ≥1 suffocation or SIDS risk factor with 54.4% infants sharing a sleep surface, 38.1% placed nonsupine, 24.2% placed on a pillow, and 10.2% having head covering. Missing data frequently resulted from incomplete scene investigation and autopsy components. SUID contributed to ≥1 in seven Florida infant deaths in 2008. Approximately 80% of sleep-related SUIDs were reported among infants placed in unsafe sleeping environments. Effective interventions are needed to promote safe sleep among caregivers of Florida infants. These interventions must reach infant caregivers at highest risk and change unsafe sleep practices. The substantial percentage of missing investigation data reinforces the need for standardized reporting.