Objective: Railway tunnel workers are exposed to excavated dust, gaseous fumes, oil vapours, etc. at their work site which may cause adverse respiratory health and decline in lung functions among these workers if safe occupational practices are insufficient. The aim of this study is the assessment of respiratory health and lung function among the tunnel workers of Riyadh metro railway tunnel. Methods: This is a cross-sectional study to monitor the respiratory health and lung functions among workers of Riyadh metro railway tunnel. Total of 87 tunnel workers were recruited for this study who were exposed with excavated dust during their work practices at the under-construction site of a metro railway tunnel. These tunnel workers were compared with 53 control subjects of same socio-economic status and were not occupationally exposed to dust before. Self-reported respiratory symptoms were obtained through the questionnaire-based survey. Spirometry was conducted for the lung function tests FEV1 (Forced expiratory volume in 1 second) and FVC (Forced vital capacity) of both exposed and control subjects. Results: Most of the symptoms reported by tunnel workers were shortness of breath (25.28%) and coughing that produces phlegm (25.28%). Both the lung function parameters viz. FEV1 and FVC were found to be significantly decreased among tunnel workers (p<0.01) as compared to control subjects. Significant negative correlation (p<0.01) was found between dust exposure period and FEV1 and FEV1/FVC. Conclusion: In conclusion, we found adverse respiratory health and decreased lung functions among tunnel workers which were also correlated with the exposure period.