In Mexico there is little research to know the magnitude of mobbing. To identify the prevalence of mobbing and characteristics associated in workers. A cross-sectional study of 499 workers who use medical unit. A questionnaire was used to determine the presence of mobbing and various instruments to know the personality, vulnerability to stress, self-esteem and depression. Prevalence odds ratio, dispersion, chi-square and Poisson regression were calculated. A prevalence of 36% was found; no significant differences between sex or school level in mobbing presence, 20.2%, were found. Sixty per cent women are perceived as victims of harassment high relative to men (p = 0.04). Workers with low self-esteem have a greater association with high mobbing (p < 0.001). The prevalence found is higher than reported in previous studies in Mexico, strong associations between mobbing and personality and emotional disorders were identified.