OBJECTIVES: To evaluate the cost effectiveness, from the Colombian health care system perspective, of ranibizumab monotherapy or ranibizumab combined with laser against laser monotherapy for the treatment of diabetic macular edema (DME). METHODS: A Markov model was designed to simulate the clinical and economic benefits associated with ranibizumab as either monotherapy or combined with laser versus laser monotherapy in the treatment of visual impairment due to DME. The effectiveness outcomes measured were the life years without visual impairment based on RESTORE 3-year follow-up data. Over 15-year time horizon annual cycles were performed. The costs involved in the model were taken from the official medication cost database in Colombia (SISMED) and 6 Colombian health care providers (IPS) The analysis, according to the RESTORE study, considered that 22 % of patients received treatment on both eyes. For ranibizumab and laser group, the first three years transition probabilities where taken from the same study and for the laser group the second and third year data was taken from the Diabetic Retinopathy Clinical Research Network (DRCR.net ). RESULTS: Ranibizumab monotherapy showed a gain of 0.30 years with no visual impairment at an incremental cost of COP 8, 272, 248 (USD 4.273,01) relative to laser monotherapy, resulting in an incremental cost- effectiveness ratio (ICER) of COP 28,041,494 (USD $14.484,77). Likewise ranibizumab monotherapy was superior to combination therapy with an ICER of COP 34,224,675 (USD $17.678, 67) in a time horizon of 15 years. Probabilistic sensitivity analysis placed ranibizumab monotherapy as a more cost-effective alternative versus laser monotherapy in 95% of the cases. CONCLUSIONS: The results pointed out that ranibizumab both as a monotherapy as well as combined with laser therapy are cost-effective alternatives from the Colombian health care system perspective.