Previous investigations have failed to show benefits of low level laser therapy (LLLT) for tendon healing in horses, contrary to reports in other species. We hypothesized that delivery of LLLT at manufacturer-recommended energy fluence through equine cadaver skin to equine tendon-derived fibroblasts in vitro would increase cell proliferation, metabolic activity and migration. Fibroblasts from grossly normal front superficial digital flexor tendons of four horses euthanatized for reasons unrelated to the study were cultured in monolayer. Cells were treated through one of three equine cadaver skin samples (light, medium, or dark colored) at manufacturer-recommended energy fluence. Untreated cells served as controls. At 24 hours after treatment, cell proliferation was determined via manual cell counts and cellular metabolic rate was assessed via resazurin sodium salt reduction assay. Cell migration was determined by scratch assay and by transwell migration assay. Data was analyzed by repeated measures ANOVA with p