Purpose - The purpose of this paper is to determine the influence of emotional and social competence (ESC) on job performance by considering self-ratings and the ratings of others (supervisor, peer and subordinate) using a multisource feedback assessment of ESC. Design/methodology/approach - The authors utilized the 2004-2006 performance evaluations of 36 staff members of the Ilo Copper Refinery, owned by the Southern Peru Corporation. To assess ESC, the Emotional Competence Inventory (ECI 2.0) was administered to the Ilo staff. Findings - The study reinforces the importance of ESC to workplace performance and provides evidence of ESC's positive influence. The results reveal that 70 percent of the variance of working performance is explained linearly by the total average of ESC, with four significant competencies self-confidence, achievement orientation, optimism, and teamwork & collaboration accounting for 63 percent of the variance. Research limitations/implications - As an initial study in Peru, the authors had a small sample size. There is limited independence in the performance evaluations because the evaluators of performance were repeated in several cases. Job performance ratings were based on the following computerized objective assessment: use of abilities, work organization planning, interpersonal relations, results, initiative, aptitude to the work, and creativity. Originality/value - The paper is aimed at improving understanding of the links between ESC and performance. It is the first study the authors are aware of to examine these relationships in a Peruvian organization. The approach used in this study contributes to and provides evidence of the importance of emotional competence in the workplace.