Eppendorf Thermomixer R is used in the diagnosis of human papilloma virus infections. With chromogenic in situ hybridization (CISH), HPV-infected cells in tissue sections are made visible to light microscopy by means of colored precipitates. The performance of Thermomixer R and ThermoStat plus is comparable to the standard method (heating plate and incubator) regarding signal intensity and unspecific background. Due to the digital temperature programming of Thermomixer R/ThermoStat plus, the results are very reproducible and less manual effort is required.