Mumps infections primarily affect childhood and the hallmark of infection is swelling of the parotid glands. The mumps cases decreased noticeably in Chile with the introduction of the triple virus vaccine. Aim: During 2018 and 2019, an outbreak occurred and affected persons between 20 and 35 years old. In the present work are the laboratory findings, carried out by the Institute of the Public Health, in the epidemiological surveillance program for mumps during this outbreak. Methods: Between January 2018 and March 2019, 592 suspected cases of viral infection were analyzed for the presence of anti-mumps virus IgM and IgG. 69 cases were analyzed by qRTPCR to evaluate the presence of viral nucleic acid in urine and saliva samples and sequencing of viral gene sh was performed. Results: The 19,8% (n= 117) and 95,9% (n= 568) of the cases were IgM and IgG positive, respectively. 56,4% (n= 66) of the IgM positive cases were men and 43,6% (n=51) were women. The distribution of the cases was between 1 to 90 years old, nevertheless 42,7% (n=50) had 20 to 29 years old. Genetic sequencing showed the presence of G and N genotype in 20 cases. Conclusions: The laboratory findings were essential for the accurate diagnosis of cases and the establishment of the outbreak by the epidemiological surveillance program.