373 cotton operatives and 295 manmade fibre operatives were administered a respiratory questionnaire on year o@ e and year three of a five year longitudinal study. A higher percentage of operatives remained asymptomatic over the three year period in manmade fibre (87.1%) than those exposed to cotton (77.4%) (p<0.01). In year one work related chronic bronchitis, non-byssinotic chest tightness and shortness of breath were significantly higher in the cotton group. However, only work related shortness of breath remained significantly higher in the cotton group for year three. Year one documented 9 operatives with byssinosis. 6 continued to present byssinotic symptoms in year three whilst 3 operatives reported a loss of their byssinotic symptoms. 5 operatives developed byssinotic symptoms in year three. Operatives reported a loss, gain or no change of symptoms whilst others remained asymptomatic between the three year study period.