Streptococcus suis is an important pathogen in the swine industry. This article is the first to report the occurrence, risk factors,serotype distribution, and antimicrobial susceptibility of S. suis recovered from employees and environmental samples of swineslaughterhouses in Brazil. Tonsillar swabs from all 139 pig-slaughtering employees and 261 environmental swabs were collectedfor detection of S. suis and serotyping by monoplex and multiplex polymerase chain reaction, respectively. Antimicrobialsusceptibility was determined by the disk-diffusion method. Although S. suis was not detected in any of the tested employees, itwas isolated from 25% of the environmental samples. Significant differences (P , 0.05) in the occurrence of S. suis were observedbetween slaughterhouses and between areas of low, medium, and high risk. The most frequent serotypes were 4 and 29, eachaccounting for 12% of the isolates, followed by 5, 12, 21, and 31, each accounting for 6%. High rates of susceptibility to theantimicrobials doxycycline (100%), ceftiofur (94%), ampicillin (81%), and cephalexin (75%) were observed. However, multidrugresistance was observed in all the isolates. Because S. suis is present in the environment of swine slaughterhouses, on carcassesand knives, as well as on the hands of employees in all areas, all employees are at risk of infection.