: The highly use of generators creating an alarming level of pollution (air and noise) in all regions of the world. The soot which is impure carbon particles emitteddfrom diesel engines into environment during combustion process is to consider one of the dangerous pollutant due to its direct and broad impact on the respiratory organs and some polycyclic aromatic hydrocarbons known for their cancer properties are associated with it. Environmental conditionsshave many serious impacts on the general health of humans-as well as on dental status. The aim of the study was to evaluate caries experience and salivary oxidative stress biomarker (protein carbonyl) in relation to dental caries among a group of diesel generator workers. The sample for this study included 94 workers in diesel generators, their ages were between 20- 49 years. Collection of stimulated salivary samples was carried out under standardized conditions to determine the level of oxidative stress biomarker (protein carbonyl) while caries experience was determined by the Decayed- Missing – Filled Surface index by WHO 1997. The result revealed that caries experience (DMFS, DMFT, DS, MS) was relatively highest among the workers with longer duration and the most component of caries experience was the Missing surfaces (MS) followed by Decayed surface(DS) while the least one was the Filling surfaces (FS), furthermore, the salivary protein carbonyl level was increased approximately with increase duration of work in the field of generators. Saliva considered as a valid and convenient diagnostic biofluid for measurement of oxidant/antioxidants in patients. In this study there was changes in the oxidative stress in the biological systems among the workers with longer duration which can be produced by the exhaustion, of antioxidants and/or by an-overload of oxidants, as a result of this ,the antioxidant defense system become deficient that may,,be important in the inflammatory reactions, also caries experience was approximately,higher=among the=workers with longer duration ,therefore special oral, and general health,,preventive and educational programs are needed for them.