Background and objectives: Cement is soft and green powder containing calcium silicate hydrate, aluminum and magnesium oxide, calcium sulfate, and clay. Exposure to cement dust is one of the factors influencing health of cement industry workers, causing different respiratory and allergic reactions. Considering the importance of workforce health, this study aimed to determine airborne concentrations and silica fraction of dust in a cement plant in South Khorasane. Methods: In this descriptive study, dust levels were determined using personal sampling method based on NIOSH 7500. 148 personal samples were taken from breathing zone of employees working in different parts of the plant. X-ray fluorescence method was used to determine silica fraction in raw material,, clinker, and cement powder. Data were analyzed by descriptive statistics using SPPS software. Results: Respirable dust concentration ranged from 0.25±0.35 in management and administration area to 12.7±30.8 mg per cubic meter in crusher area. Inhalable and respirable dust concentrations were higher than threshold limit values (TLV) in all plant areas except the management and administrative area. Silica fractions were determined to be 22 in cement and clinker and 15% in raw materials. Conclusion: Concentrations of inhalable and respirable cement dusts are much higher than those of occupational exposure limits proposed by Iranian Technical Committee of Occupational Health. Occupational exposure of all employees working in “production line” is higher than the permissible limit.