Biofilm formation on surfaces has important consequences for health and the food industry because it can be a source of food contamination that causes food spoilage and foodborne diseases. The present study evaluated the effect of thyme essential oil (EO), and its fractions, carvacrol and thymol, against Salmonella Saintpaul biofilms on polypropylene (PP) surface. Thyme was purchased from a local market and the EO was obtained by hydrodistillation using a Clevenger-type apparatus. The chemical composition was investigated by gas chromatography-mass spectrometry and nuclear magnetic resonance. Minimum inhibitory concentration (MIC) for thyme EO, carvacrol, thymol, borneol and p-cimeno were determined according to document M7-A8 - Clinical and Laboratory Standards Institute. Biofilms were left to be formed on PP coupons with sub inhibitory concentrations (0.5 and 0.75 MIC) of thyme EO, carvacrol and thymol for 48 h at 35°C. After incubation, the coupons were submitted to ultrasonic bath (25 KHz/ 5 min), plated on Mueller Hinton Agar and incubated for 24 h at 35°C. Borneol and p-cimeno did not show antimicrobial activity at the highest concentration tested, not being tested on biofilm assay. Thyme EO did not reduced biofilm formation. Carvacrol and thymol were able to decrease about 1 to 3 log CFU/cm2 of bacteria on PP. These compounds showed effect on biofilm formation of S. Saintpaul and may be used as alternative to chemical disinfectants in food industry.