Economic evaluation of an intervention promoting adoption of occupational sun protection actions by Colorado public sector employers. Randomized controlled trial with 2-year follow-up conducted during 2010 to 2013. Thirty-three intervention and 30 attention-control worksites in final economic sample. Twenty-four-month intervention of personal contacts, training, and materials. Intervention delivery micro-costed. Costs of implemented actions from employer self-report. Twenty-four-month intervention costs: $121,789, 51.8% incurred by project staff (per-worksite mean=$1,732). Worksite costs: $58,631 (mean = $1,777). Per-employee costs: $118 project staff, $56 worksites. Materials cost: $5990 (mean = $181). Intervention worksites implemented 72 nontraining sun protection actions post-Sun Safe Workplaces (SSW) (mean = 2.18). Control worksites implemented 39 actions (mean = 1.30). Total costs to intervention worksites of implementing the 72 post-SSW actions: $90,645 (mean = $2,747). Control worksite costs: $66,467 (mean = $2,216). Per-employee implementation costs are comparable to other worksite health interventions. SSW expanded adoption of sun protection actions at a reasonable per-employee cost.