OBJECTIVES: To compare Ertapenem with ceftriaxone for the treatment of urinary tract infections (UTI) in Colombia healthcare setting, with respect to cost and outcomes taking into account development of anti-microbial resistance (AMR). METHODS: A previously published decision tree model was adapted to estimate cost-effectiveness of Ertapenem vs. Ceftriaxone in the treatment of UTI. Clinical efficacy, adverse events and medical resource use were derived from literature. AMR to Ertapenem and ceftriaxone was calculated as weighted average based on the % distribution of different pathogens in UTI in Colombia and the sensitivity of Ertapenem and Ceftriaxone to each pathogen from Colombia SMART data. The resistance-adjusted effectiveness is then computed based on the efficacy from clinical trial and local AMR data, Model outcomes included resistance, clinical success, deaths, life years, direct costs, and costs per successfully treated patient. RESULTS: The overall AMR of Ertapenem vs. Ceftriaxone for UTI is 7% vs. 30%. The resistance-adjusted effectiveness is 83% vs. 64% for Ertapenem vs. Ceftriaxone. Daily drug costs for Ertapenem vs. Ceftriaxone are 133,550 vs. 8,550 Colombian Pesos. Total costs (including drug costs, hospitalization, cost of 2^nd-line treatment & cost of AEs) are 446,871 vs. 188,268 Pesos. During the first hospitalization period, Ertapenem is associated with a 18.8% higher treatment success rate, and 178,377 Pesos more in total cost when compared with Ceftriaxone. The incremental cost per successfully treated patient (ICER) is 9,488 Pesos ($4.87 USD) for Ertapenem vs. Ceftriaxone. CONCLUSIONS: Accounting for local anti-microbial resistance, Ertapenem is more effective as well cost-effective vs. Ceftriaxone for the treatment of urinary tract infections in Colombia.