The act of voting is one of the most representative of Democracy, being widely recognized as a fundamental right of citizens. The method of voting has been the subject of many studies and improvements over time. The introduction of electronic voting or e-voting demands the fulfillment of several requirements in order to maintain the security levels of the paper ballot method and the degree of trust people place in the voting process. The ability to meet those requirements has been called into question by several authors. This exploratory research aims to identify what factors influence voters' confidence in e-voting systems. A case study was conducted in an organization where such a system has been used in several elections. A total of 51 e-voters were interviewed. The factors that were found are presented and discussed, and proposals for future work are suggested.