Since its introduction by the military regime, Chile’s binominal system has continuously been questioned. This is the reason for thinking about an electoral reform, although some of its effects empirically have benefited the democratic development of the country. The same result is obtained, if –at a theoretical level- the effects of the binominal system are considered comparatively, applying criteria of evaluation which stem from world wide processes of electoral reform. Nevertheless, some weaknesses of the binominal system concerning the function of representation can be observed. A reform, addressing these weaknesses, should at the same time try to maintain the effectiveness of the system with regard to other functions like concentration and participation. This includes defending the system against critics which focus on phenomena like clientelism, surely caused by other factors than the binominal system. Concerning the design itself, the paper suggests first to define the objectives of a reform, that means forming consensus, and than to work on the technical aspects of the concrete system. Furthermore it reminds academics and legislators of the comparative experience that the electoral system in force is usually the most probable option under the considered alternatives.El sistema binominal continúa siendo cuestionado, razón por la cual parece conveniente su reforma, pese a que sus efectos han sido empíricamente bastante beneficiosos. El mismo balance se desprende, a nivel teórico, comparando los efectos del sistema electoral vigente en Chile con criterios de evaluación que se expresan homogénea y universalmente en procesos de reforma electoral. Sin embargo, hay debilidades del sistema binominal en la función de representación que conviene subsanar, tratando de conservar su efectividad respecto a otras funciones. Esto incluye también defenderlo frente a críticas que se centran en fenómenos como el clientelismo, cuyas causas están fuera de su alcance. Respecto al diseño mismo, se sugiere entenderse primero sobre los objetivos de la reforma: formar consenso, sólo después tratar los elementos técnicos de su materialización. Se recuerda, además, que desde una perspectiva comparativa el sistema vigente es a menudo la solución más probable entre las alternativas en debate.