Background Textile cotton workers are at risk for occupational lung disease, including Byssinosis and chronic Bronchitis Byssinosis is primarily associated with exposure to cotton dust Objectives To determine the prevalence of and factors associated with byssinosis and respiratory symptoms among workers in cotton mills of Akaki textile factory Methods A cross-sectional study was conducted among 417 randomly selected factory workers Information was collected through interview using the modified American Thoracic Society standard respiratory symptoms questionnaires Forced expiratory volume in 1 sec (FEV1), forced vital capacity (FVC) and FEV1/FVC ratio were measured using portable medical spirometers Area sampling for cotton dust concentration in the work environment was measured using Data RAM 4 real time measurement for 8 hours during a day shift Results The highest prevalence of respiratory symptoms was found in the carding section - cough 77%, phlegm 62%, chest tightness 46% and dyspnea 62% The Overall prevalence of chronic bronchitis was 32% Those working m the carding section appeared 13 times more likely to have chronic bronchitis compared to other sections (Adjusted OR=13 4, 95% CI 3 43-52 6) The prevalence of byssinosis was 38%, the highest being recorded m the carding section at 84 6% High exposure to cotton dust was noted among those in the blowing and carding section at mean dust levels of 32 2 mg/m(3) and 8 mg/m(3), respectively About 11% of byssinotics developed severe chronic FEV1 changes Conclusion This study provides evidence of a strong relationship between exposure to cotton dust and byssinosis and other respiratory impairments, which is mediated through chronic ventilator impairments Preventive measures are warranted in order to reduce the high prevalence of byssinosis and other respiratory disorders in textile manufacturing [Ethiop J Health Dev 2010,24(2) 133-139]