Introduction: Asphalt mixing plants' workers are exposed to different types of chemicals at the work place that may affect their respiratory system. Aim of Work: To study the respiratory health disorders among asphalt mixing plants' workers and to assess the workplace environment. Materials and Methods: A cross sectional study was conducted in 2 asphalt mixing plants, Menoufia Governorate and 100 asphalt mixing plants' workers have been included in the study during the period from the February 1st, 2020 to December 31th, 2021. An equal number of control subjects were chosen at random from workers' family members with the same socio-demographic characteristics and who had never been exposed to such risks. A predesigned questionnaire was used for interviewing all participants followed by physical examination and spirometric measurements. Assessment of the work environment was also done. Results: The average concentration of airborne particles was (3.872 0.307 mg/m3), which was higher than the Egyptian Environmental Law 4 Decree 1095, (2011) permitted threshold of (3 mg/m3). Furthermore, the total accumulation of crystalline silica in airborne particles was (45.58 2.531mg/m3), which was less than the acceptable amount established by Egyptian Environmental Law No. 4 Decree 1095, 2011 and Recommended Exposure Limit (REL) of NIOSH, 2005 for free crystalline silica level (50 μg/m3 = 0.05 mg/m3). Respiratory symptoms such as rhinitis, cough, productive cough, dyspnea, wheezes, and asthma were more common among workers exposed to free crystalline silica (60%, 62%, 35%, 67%, 31% and 24%; respectively), as well as spirometric measurements were statistically significantly lower compared to the controls (p < 0.05). Significant negative correlation between work duration and FVC% and FEV1% were detected (p ≤0.05). Conclusion and Recommendations: Working in asphalt mixing plants with exposure to free crystalline silica has been found to affect the respiratory system and induce decline in spirometric measurements. It's recommended that personal protective equipment should be regularly used with proper ventilation of the workplace and continuous monitoring of the work environment to maintain the exposure levels below permissible values. Also, all workers should be subjected to periodic medical examination.