Introduction: The Call Center Phone Operator is subject to environmental noise and to the headphones volume sound with possible hearing loss effects. Objectives: The main objective of the study was to assess whether the type of headphone system used by call center operators incidenced the asymmetrical hearing loss. Material and methods: Descriptive observational study carried out on teleoperators of a call centre in the south of Spain. Opportunity sampling technique carried out from the health surveillance examination from 2018, with audiometry and self-completed questionnaire. The dependent variable was the presence of asymmetric hearing loss (interaural threshold value of 15 dB or more in at least one frequency). Bivariate analysis was performed, and statistical programs SPSS version 25 and EPIDAT version 4.2 were used. Results: Asymmetric hearing loss in the studied sample was significantly related to the age of the subjects (Z =-3,606, p<0,000), but not to the type of headphone system used or to other socio-demographic, occupational or clinical variables analysed. Conclusions: The use of mono headphones does not seem to be related with an asymmetric hearing loss in the telephone operators of the studied sample.