Anti-cancer therapeutic peptides have been applied in developing cancer therapeutics focusing on small molecular weight peptides with strong tumoricidal activity and low toxicity. RRM-MV is a bioactive peptide analogue for myxoma virus protein (M-T5) designed by the Resonant Recognition Model (RRM) as a linear short peptide. M-T5 is an ankyrin-repeat protein which is known to be critical for virus replication in the majority of human tumor cells. The non-bioactive peptide RRM-C was also designed by the RRM with a different inactive frequency, and was used as a negative control peptide. The aim of this study was to estimate the biological influence of the bioactive peptide RRM-MV on cell viability of human skin cancer and normal cell lines. The toxic activity of RRM-MV was determined on melanoma cells (MM96L), carcinoma cells (COLO-16) and normal skin cells (HDF) at various doses and incubation times using the Prestoblue cell viability assay. The degree of cell recovery in the treated cells was also evaluated. Our results demonstrated that RRM-MV produced a time and dose dependent cytotoxic effect on the cancer cells, while it had a negligible effect on normal cells. However, the cancer cells were recovered after 16 h of the treatments, indicating the need for a second dose. Treatment of the cancer cells with a second dose of RRM-MV had a significant effect affected on cell growth. Interestingly, no effects on growth of either cancer or normal cells were detected following treatment with RRM-C. Therefore, it can be suggested that the RRM is a valid tool to design bioactive peptides with targeted therapeutic functions.